[8525, TyTN, MDA Vario II, JasJam Software Upgradin] mixersoft:
I bought a Softbank X01HT after finding this site, and as a total WM5 newbie, decided I would switch the phone from Japanese to English. It took me 5 days of lurking around this site, but I finally did it. Here's a summary of my efforts for those of you who dare follow:

Unlock the phone

I went here to get it done: http://www.imei-check.co.uk

Download and Install English ActiveSync from Microsoft

Get it here:http://www.microsoft.com/windowsmobile/activesync/default.mspx

I'm using v4.2

Disable Advanced USB Networking

If ActiveSync keeps disconnecting on USB, then go to Settings > Connections > Usb to PC, and disable advance network funtctionality.

Here's the thread that describes the problem: http://xdaforums.com/showthread.php?t=276783

Flash with an English ROM

Here's the post that I followed: http://xdaforums.com/showthread.php?t=280566&page=7

Here's the ROM for JASJAM_WWE_1.20.305.3_1.20.305.104_1.07.03.10_ship

Note: the ROMs and the ExtendedROMs are not the same. The Flash will take about 30 mins. It will reset when done, and then ask you to align the screen. I just did as I was told. when done, it automatically started to load the included ExtendedROMs.

Unhide Extended ROM folder

Install fit4cat Hermes Tweaker, I used v1.1a. Get it here: http://www.fit4cat.de/thread.php?threadid=56

From the earlier post, enable 'HSPDA settings' and check all the boxes on the 'security' tab (mount extROM, unlock extROM, allow non certified apps)

Install the Softbank Extended ROMs

Get the Softbank Extended ROMs from this page: http://wiki.xda-developers.com/index.php?pagename=Hermes_ExtendedRoms

Move the contents of the folder to your /ExtendedROM folder then do a HARD reset

How to do a HARD Reset

The instructions for a HARD reset are located here: http://wiki.xda-developers.com/index.php?pagename=Hermes_Resets

Make sure you see the menu with the press 'R' to reset. If you don't, you didn't do it right. Try it again.

Apparently, after a Hard reset, you will automatically start the 'autorun' script for the Softbank Extended ROMs, and this will add the settings for using data over the Softbank 3G network. If you still don't get a data connection to the Softbank Network, you can add it manually. Read this page for details (#17): http://xdaforums.com/showthread.php?t=280566&page=2

Install a Registry Editor

I chose the one included in the Resco Explorer. Even though your processor is by Samsung, make sure you download the CABs for the ARM/Xscale processor.

Get it here: http://www.resco.net/pocketpc/explorer/indepth.asp

Note: you have to install the Explorer and the Registry Editor plugin

Do the Japanese Keyboard Hack

The key thing to remember is that even though your Hermes speaks English, the keyboard uses a Japanese layout. The code for Japanese is 0x0411

[HKEY_CURRENT_USER\ControlPanel\Keybd] "Locale"= 0411 (Hex, not String)

[HKEY_LOCAL_MACHINE\Software\Oem\Qwerty] "Layout"= 20411 (Hex)

[HKEY_CURRENT_USER\keyboard layout\Preload] "Default"= e0010411 (Hex)

[HKEY_CURRENT_USER\keyboard layout\Preload\1] "Default"= e0010411 (Hex)

Install Japanese Language Fonts

Now that your Hermes speaks English, you can't see Japanese Web pages. This CAB will fix it. Get it here: http://asukal.seesaa.net/article/6912738.html

Install BTaudio Hack

This hack lets you route the PDA audio to your Bluetooth headset. Without it, you can only use the headset for the phone. It worked fine with my Motorola HS850 set to the "Hands Free" BT profile. I used the version from this post (includes a link to the CAB): http://xdaforums.com/showthread.php?p=1044017#post1044017

and Voila! you are ready to go.

Of course, before you start you should read the following:

http://wiki.xda-developers.com/index.php?pagename=Hermes_For_Beginners

http://wiki.xda-developers.com/index.php?pagename=Hermes_UpgradeFAQ

http://wiki.xda-developers.com/index.php?pagename=Hermes_UpgradeProblems

The above is a summary of what I did, and it worked for me. But, of course, nothing is warranted and proceed at your own risk. yada yada.