I purchased an hw6945 in January. It works fine on T-Mobile. It did take over an hour with technical support to get the Multimedia Messaging Service (MMS) working. The settings that worked are different from those on the T-Mobile phone configurator. See below for my settings. I don't know if this changes in different regions.
Picture Messaging (MMS) Configuration
These instructions will help you configure your phone for picture messaging (MMS).
1. On the handset, tap on the Start button.
2. Tap on Settings.
3. Tap on Connections.
4. Tap on the Connections icon.
5. Under My ISP, tap on Add a new modem connection.
6. Enter GPRS T-Mobile US in the Enter a name for the connection field.
7. Select Cellular Line (GPRS) in the drop down list of Select a modem.
8. Tap Next.
9. Enter internet3.voicestream.com in the Access point name field. Tap Next.
10. Enter in the User name field.
11. Enter in the Password field.
12. Tap Advanced.
13. Select Use server-assigned IP address. Tap OK.
14. Tap Finish.
15. Tap OK.
16. Tap on Start button.
17. Tap on Messaging.
18. Tap on Menu which is located at the bottom right corner.
19. Tap on MMS Configuration.
20. Under Servers, tap on New.
21. Enter T-Mobile US MMS in the Server name field.
22. Enter 216.155.165.050 in the Gateway field.
23. Enter 9201 in the Port number field.
24. Enter
http://216.155.174.84/servlets/mms in the Server Address field.
25. Select T-Mobile US MMS in the Connect via drop down selection.
26. Select WAP 1.2 in the WAP Version drop down selection.
27. Tap on OK.
28. Tap on Set As Default.
29. Tap OK.
The handset is now configured for using Multimedia Messages.