ok,for S&Gs,i stuck my t mobile sim into my merge,running nTelos GB. without further mods,calls and texts were working. no data or mms.
i sis a quick search for t mobile APNs,and came across this:
Support: Verify the Access Point Name (APN) and internet data connection - T-Mobile myTouch 3G / myTouch 3G Slide / myTouch 4G
i entered the following as a new APN:
Name: T-Mobile Data (or T-Mobile US)
APN: epc.tmobile.com
Proxy: <Not set>
Port: <Not set>
Username: None
Note: For the Username, enter "None" with the keypad. Do not leave it not set.
Password: <Not set>
Server: <Not set>
MMSC: http://mms.msg.eng.t-mobile.com/mms/wapenc
MMS proxy: <Not set>
MMS port: <Not set>
MMS protocol: WAP 2.0
MCC: 310
MNC: 260
Authentication type: <Not set>
APN type: default,supl,admin,dun,mms
Press the Menu key.
Touch Save.
saved it,exited back to the home screen,lo and behold,edge data

mms appears to be working as well.
enter the new APN info at: menu softkey/settings/wireless & networks/mobile networks/GSM/UMTS options/acess point names
its had to remember exactly what id tried when messing with this before,but i know for sure its working with nTelos 3.08.557.1 and the above APN. if i have a chance ill try and verify it on some other ruus as well. hope it helps