[JASJAR, XDA Exec, MDA Pro Software Upgrading] eagle 1:
Here's what I use for T-Mobile USA. Hope it helps. Just change the keys to your operator settings.

<wap-provisioningdoc>

<characteristic type="CM_ProxyEntries">

<characteristic type="WAP-{18AD9FBD-F716-ACB6-FD8A-1965DB95B814}">

<parm name="SrcId" value="{18AD9FBD-F716-ACB6-FD8A-1965DB95B814}" />

<parm name="DestId" value="{7022E968-5A97-4051-BC1C-C578E2FBA5D9}" />

<parm name="Proxy" value="216.155.165.50:9201" />

<parm name="Type" value="2" />

<parm name="Enable" value="1" />

</characteristic>

</characteristic>

<characteristic type="CM_GPRSEntries">

<characteristic type="T-Zones GPRS">

<parm name="DestId" value="{ADB0B001-10B5-3F39-27C6-9742E785FCD4}" />

<parm name="Enabled" value="1" />

<parm name="UserName" value="" />

<parm name="Password" value="" />

<parm name="Domain" value="" />

<parm name="SpecificIpAddr" value="0" />

<parm name="IpAddr" value="" />

<parm name="SpecificNameServers" value="0" />

<parm name="DnsAddr" value="" />

<parm name="AltDnsAddr" value="" />

<parm name="WinsAddr" value="" />

<parm name="AltWinsAddr" value="" />

<characteristic type="DevSpecificCellular">

<parm name="BearerInfoValid" value="1" />

<parm name="GPRSInfoValid" value="1" />

<parm name="GPRSInfoProtocolType" value="2" />

<parm name="GPRSInfoL2ProtocolType" value="PPP" />

<parm name="GPRSInfoAccessPointName" value="internet2.voicestream.com" />

<parm name="GPRSInfoAddress" value="" />

<parm name="GPRSInfoDataCompression" value="1" />

<parm name="GPRSInfoHeaderCompression" value="1" />

<parm name="GPRSInfoParameters" value="" />

</characteristic>

</characteristic>

<characteristic type="T-Mobile WAP">

<parm name="DestId" value="{18AD9FBD-F716-ACB6-FD8A-1965DB95B814}" />

<parm name="Enabled" value="1" />

<parm name="UserName" value="" />

<parm name="Password" value="" />

<parm name="Domain" value="" />

<parm name="SpecificIpAddr" value="0" />

<parm name="IpAddr" value="" />

<parm name="SpecificNameServers" value="0" />

<parm name="DnsAddr" value="" />

<parm name="AltDnsAddr" value="" />

<parm name="WinsAddr" value="" />

<parm name="AltWinsAddr" value="" />

<characteristic type="DevSpecificCellular">

<parm name="BearerInfoValid" value="1" />

<parm name="GPRSInfoValid" value="1" />

<parm name="GPRSInfoProtocolType" value="2" />

<parm name="GPRSInfoL2ProtocolType" value="PPP" />

<parm name="GPRSInfoAccessPointName" value="wap.voicestream.com" />

<parm name="GPRSInfoAddress" value="" />

<parm name="GPRSInfoDataCompression" value="1" />

<parm name="GPRSInfoHeaderCompression" value="1" />

<parm name="GPRSInfoParameters" value="" />

</characteristic>

</characteristic>

</characteristic>

<characteristic type="Registry">

<characteristic type="HKLM\Software\CDL">

<parm name="Operator" value="T-Mobile Internet US" datatype="string"/>

<parm name="Version" value="2.0" datatype="string"/>

</characteristic>

</characteristic>

<characteristic type="Registry">

<nocharacteristic type="HKLM\Software\Apps\i-mate T-Mobile Internet US"/>

<nocharacteristic type="HKLM\Security\AppInstall\i-mate T-Mobile Internet US"/>

<nocharacteristic type="HKLM\Security\AppInstall\i-mate T-Mobile Internet US\ExecutableFiles"/>

</characteristic>