People with T-Zones, try this Settings...
It should work!

Cellular Data

APN: epc.tmobile.com
USERNAME: (leave blank)
PASSWORD: (leave blank)

MMS

APN: epc.tmobile.com
USERNAME: (leave blank)
PASSWORD: (leave blank)
MMSC: http://mms.msg.eng.t-mobile.com/mms/wapenc
MMS PROXY: 216.155.165.50:8080
MMS MAX MESSAGE SIZE: (leave blank)
MMS UA PROF URL: (leave blank)


(Also, feel free to ask me any questions)

EDIT (REPLY TO IRONICNY): I finally got EPC to work with MMS, see settings above.

Steps I took:

1) Made sure I did not have "AsBattery" installed.
2) Installed "ActivateMMS2G"
3) Reboot Device.
4) Setup up MMS on Cellular Data Network (with the information above)
5) Reboot Device.
6) Made sure Message Settings had MMS turned on
7) Tested Sending MMS = OK / Tested Receiving MMS = OK



its didnt work for me ... but other people swear off it... im still on the hunt lol