If you have a GPS radio 3.**.** you should have GPS for MMS have you tried installing a Metro wap/mms cab. I might be able to help you with out reflashing the phone. Post the following
current ROM
Radio version
what Gps program you are trying to use
and if you have internet
If you need a metro cab for wap mms let me know and I'll give you a link.
Here is the setting for manual entry for wap mms
http://forum.xda-developers.com/showthread.php?t=448955