Q: I would like to configure my Diamond card account on my mobile. My mobile brand (HTC HD MINI) with Windows Mobile 6.
A: These two articles describe how to configure native Windows Mobile SIP:
http://www.sems.org/entry.asp?ENTRY_ID=211
http://forum.xda-developers.com/showthread.php?t=299950
You'll need to use the following SIP settings to use it with Diamondcard: Generic SIP settings