I was having trouble getting the MMS working on the SMT5600 with T-Mobile. I have it working so I thought I would pass it on.
1.Set up Start>Configurations>MMS Settings.Menu>New per the screenshot below. MMSC should read
http://216.155.174.84/servlets/mms2. Set Setting>Data Connections>Internet Connections to the wap.voicestream.com access point. I have internet2 but only wap worked for me to send and receive MMS message. Set the wap.voicestream to Internet as normal.
3. Go to MMS and send your own email or your telephone number a MMS messgae. It takes a few seconds to send. It also takes T-Mobile awhile to forward it on. I mean maybe minutes once they get it. That is it.
Just a note: Using the wap.voicestream.com access point has always worked the same as internet2 for me even doing laptop modem etc. I think T-Mo looks at what ports you are authorized for no matter what access point you use. However MMS seems asscoiated with the wap server.
4. Remember you may pay extra for MMS transmissions.
The attached ZIP includes an MMS set up CAB.
(IMG:
http://www.abatis.us/SMT5600/Conf-MMS1.jpg) (IMG:
http://www.abatis.us/SMT5600/Conf-MMS2.jpg)