[Sony Xperia T, TL, TX, V] Rycon33:
For adding "permanent" menu:

Decompile SystemUI.apk and go to SystemUI\smali\com\android\systemui\statusbar\phone, open the file NavigationBarView.smali and do the edit as below:

Look for .method public setDisabledFlags(IZ)V

Just immediately below that line, add one number to .locals because we're adding one new variable, it will look like below:

.method public setDisabledFlags(IZ)V
[COLOR="Red"].locals 8[/COLOR]
.parameter "disabledFlags"
.parameter "force"

Originally mine was .locals 7, so I just increase it to .locals 8

Further down below you will see this line:

invoke-virtual {p0}, Lcom/android/systemui/statusbar/phone/NavigationBarView;->getHomeButton()Landroid/view/View;

move-result-object [COLOR="red"][B]v6[/B][/COLOR]

Insert the below line immediately after the code above.

[COLOR="Blue"][B]invoke-virtual {p0}, Lcom/android/systemui/statusbar/phone/NavigationBarView;->getMenuButton()Landroid/view/View;

move-result-object [COLOR="red"][B]v7[/B][/COLOR][/B][/COLOR]

And a little further down, you will see this:

invoke-virtual {[COLOR="red"][B]v6[/B][/COLOR], v3}, Landroid/view/View;->setVisibility(I)V

Insert the below line immediately after the code above.

[COLOR="Blue"][B]invoke-virtual {[COLOR="red"][B]v7[/B][/COLOR], v3}, Landroid/view/View;->setVisibility(I)V[/B][/COLOR]

Be mindful of V#, if previous is v6, you make yours to be v7

Next, find these two methods: .method public setMenuVisibility(Z)V and .method public setMenuVisibility(ZZ)V

Delete most of the contents of those two methods leaving it to look just like below:

.method public setMenuVisibility(Z)V
.locals 1
.parameter "show"

return-void
.end method

.method public setMenuVisibility(ZZ)V
.locals 2
.parameter "show"
.parameter "force"

return-void
.end method

Save your file NavigationBarView.smali, then proceed editing the navigation_bar.xml in SystemUI\res\layout.

Just copy mine replacing your original:

<?xml version="1.0" encoding="utf-8"?>
<com.android.systemui.statusbar.phone.NavigationBarView android:background="#ff000000" android:layout_width="fill_parent" android:layout_height="fill_parent" android:directionality="none"
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:systemui="http://schemas.android.com/apk/res/com.android.systemui">
<FrameLayout android:id="@id/rot0" android:layout_width="fill_parent" android:layout_height="fill_parent">
<LinearLayout android:orientation="horizontal" android:id="@id/nav_buttons" android:clipChildren="false" android:clipToPadding="false" android:layout_width="fill_parent" android:layout_height="fill_parent" android:animateLayoutChanges="true">
<View android:visibility="invisible" android:layout_width="fill_parent" android:layout_height="fill_parent" android:layout_weight="1.0" />
<com.android.systemui.statusbar.policy.KeyButtonView android:id="@id/back" android:layout_width="80.0dip" android:layout_height="fill_parent" android:src="@drawable/ic_sysbar_back" android:layout_weight="0.0" android:contentDescription="@string/accessibility_back" systemui:keyCode="4" systemui:glowBackground="@drawable/ic_sysbar_highlight" />
<View android:visibility="invisible" android:layout_width="fill_parent" android:layout_height="fill_parent" android:layout_weight="1.0" />
<com.android.systemui.statusbar.policy.KeyButtonView android:id="@id/home" android:layout_width="80.0dip" android:layout_height="fill_parent" android:src="@drawable/ic_sysbar_home" android:layout_weight="0.0" android:contentDescription="@string/accessibility_home" systemui:keyCode="3" systemui:keyRepeat="false" systemui:glowBackground="@drawable/ic_sysbar_highlight" />
<View android:visibility="invisible" android:layout_width="fill_parent" android:layout_height="fill_parent" android:layout_weight="1.0" />
<com.android.systemui.statusbar.policy.KeyButtonView android:id="@id/menu" android:layout_width="80.0dip" android:layout_height="fill_parent" android:src="@drawable/ic_sysbar_menu" android:layout_weight="0.0" android:contentDescription="@string/accessibility_menu" systemui:keyCode="82" systemui:glowBackground="@drawable/ic_sysbar_highlight" />
<View android:visibility="invisible" android:layout_width="fill_parent" android:layout_height="fill_parent" android:layout_weight="1.0" />
<com.android.systemui.statusbar.policy.KeyButtonView android:id="@id/recent_apps" android:layout_width="80.0dip" android:layout_height="fill_parent" android:src="@drawable/ic_sysbar_recent" android:layout_weight="0.0" android:contentDescription="@string/accessibility_recent" systemui:glowBackground="@drawable/ic_sysbar_highlight" />
<View android:visibility="invisible" android:layout_width="fill_parent" android:layout_height="fill_parent" android:layout_weight="1.0" />
</LinearLayout>
<LinearLayout android:orientation="horizontal" android:id="@id/lights_out" android:visibility="gone" android:layout_width="fill_parent" android:layout_height="fill_parent">
<View android:visibility="invisible" android:layout_width="fill_parent" android:layout_height="fill_parent" android:layout_weight="1.0" />
<ImageView android:layout_width="80.0dip" android:layout_height="fill_parent" android:src="@drawable/ic_sysbar_lights_out_dot_small" android:scaleType="center" android:layout_weight="0.0" />
<View android:visibility="invisible" android:layout_width="fill_parent" android:layout_height="fill_parent" android:layout_weight="1.0" />
<ImageView android:layout_width="80.0dip" android:layout_height="fill_parent" android:src="@drawable/ic_sysbar_lights_out_dot_large" android:scaleType="center" android:layout_weight="0.0" />
<View android:visibility="invisible" android:layout_width="fill_parent" android:layout_height="fill_parent" android:layout_weight="1.0" />
<ImageView android:layout_width="80.0dip" android:layout_height="fill_parent" android:src="@drawable/ic_sysbar_lights_out_dot_large" android:scaleType="center" android:layout_weight="0.0" />
<View android:visibility="invisible" android:layout_width="fill_parent" android:layout_height="fill_parent" android:layout_weight="1.0" />
<ImageView android:layout_width="80.0dip" android:layout_height="fill_parent" android:src="@drawable/ic_sysbar_lights_out_dot_small" android:scaleType="center" android:layout_weight="0.0" />
<View android:visibility="invisible" android:layout_width="fill_parent" android:layout_height="fill_parent" android:layout_weight="1.0" />
</LinearLayout>
<com.android.systemui.statusbar.policy.DeadZone android:layout_gravity="top" android:id="@id/deadzone" android:layout_width="fill_parent" android:layout_height="@dimen/navigation_bar_deadzone_size" />
</FrameLayout>
<FrameLayout android:id="@id/rot90" android:paddingTop="0.0dip" android:visibility="gone" android:layout_width="fill_parent" android:layout_height="fill_parent">
<LinearLayout android:orientation="vertical" android:id="@id/nav_buttons" android:clipChildren="false" android:clipToPadding="false" android:layout_width="fill_parent" android:layout_height="fill_parent" android:animateLayoutChanges="true">
<View android:visibility="invisible" android:layout_width="fill_parent" android:layout_height="fill_parent" android:layout_weight="1.0" />
<com.android.systemui.statusbar.policy.KeyButtonView android:id="@id/recent_apps" android:layout_width="fill_parent" android:layout_height="80.0dip" android:src="@drawable/ic_sysbar_recent_land" android:layout_weight="0.0" android:contentDescription="@string/accessibility_recent" systemui:glowBackground="@drawable/ic_sysbar_highlight_land" />
<View android:visibility="invisible" android:layout_width="fill_parent" android:layout_height="fill_parent" android:layout_weight="1.0" />
<com.android.systemui.statusbar.policy.KeyButtonView android:id="@id/menu" android:layout_width="fill_parent" android:layout_height="80.0dip" android:src="@drawable/ic_sysbar_menu_land" android:layout_weight="0.0" android:contentDescription="@string/accessibility_menu" systemui:keyCode="82" systemui:glowBackground="@drawable/ic_sysbar_highlight_land" />
<View android:visibility="invisible" android:layout_width="fill_parent" android:layout_height="fill_parent" android:layout_weight="1.0" />
<com.android.systemui.statusbar.policy.KeyButtonView android:id="@id/home" android:layout_width="fill_parent" android:layout_height="80.0dip" android:src="@drawable/ic_sysbar_home_land" android:layout_weight="0.0" android:contentDescription="@string/accessibility_home" systemui:keyCode="3" systemui:keyRepeat="false" systemui:glowBackground="@drawable/ic_sysbar_highlight_land" />
<View android:visibility="invisible" android:layout_width="fill_parent" android:layout_height="fill_parent" android:layout_weight="1.0" />
<com.android.systemui.statusbar.policy.KeyButtonView android:id="@id/back" android:layout_width="fill_parent" android:layout_height="80.0dip" android:src="@drawable/ic_sysbar_back_land" android:layout_weight="0.0" android:contentDescription="@string/accessibility_back" systemui:keyCode="4" systemui:glowBackground="@drawable/ic_sysbar_highlight_land" />
<View android:visibility="invisible" android:layout_width="fill_parent" android:layout_height="fill_parent" android:layout_weight="1.0" />
</LinearLayout>
<LinearLayout android:orientation="vertical" android:id="@id/lights_out" android:visibility="gone" android:layout_width="fill_parent" android:layout_height="fill_parent" android:directionality="none">
<View android:visibility="invisible" android:layout_width="fill_parent" android:layout_height="fill_parent" android:layout_weight="1.0" />
<ImageView android:layout_width="fill_parent" android:layout_height="80.0dip" android:src="@drawable/ic_sysbar_lights_out_dot_small" android:scaleType="center" android:layout_weight="0.0" />
<View android:visibility="invisible" android:layout_width="fill_parent" android:layout_height="fill_parent" android:layout_weight="1.0" />
<ImageView android:layout_width="fill_parent" android:layout_height="80.0dip" android:src="@drawable/ic_sysbar_lights_out_dot_large" android:scaleType="center" android:layout_weight="0.0" />
<View android:visibility="invisible" android:layout_width="fill_parent" android:layout_height="fill_parent" android:layout_weight="1.0" />
<ImageView android:layout_width="fill_parent" android:layout_height="80.0dip" android:src="@drawable/ic_sysbar_lights_out_dot_large" android:scaleType="center" android:layout_weight="0.0" />
<View android:visibility="invisible" android:layout_width="fill_parent" android:layout_height="fill_parent" android:layout_weight="1.0" />
<ImageView android:layout_width="fill_parent" android:layout_height="80.0dip" android:src="@drawable/ic_sysbar_lights_out_dot_small" android:scaleType="center" android:layout_weight="0.0" />
<View android:visibility="invisible" android:layout_width="fill_parent" android:layout_height="fill_parent" android:layout_weight="1.0" />
</LinearLayout>
<com.android.systemui.statusbar.policy.DeadZone android:layout_gravity="left" android:id="@id/deadzone" android:layout_width="@dimen/navigation_bar_deadzone_size" android:layout_height="fill_parent" />
</FrameLayout>
<View android:id="@id/rot270" android:visibility="gone" android:layout_width="fill_parent" android:layout_height="fill_parent" />
</com.android.systemui.statusbar.phone.NavigationBarView>