Alltel Diamond and SMS/MMS

[Crisis]

Hi everyone. I'm very new to the forum but I'm hoping I can get some help potentially. I got a Touch Diamond very recently and I am having no trouble installing ROMs and all of that great stuff. Thanks to all who make these things because the devices run infinitely better on those than what Alltel ships theirs with.

The issue I'm having is with SMS and MMS. Thus far I have been completely unsuccessful in getting any ROM to work with my Diamond and SMS/MMS. Seriously I've tried a bunch of different carrier cabs with multiple ROMs including Mighty's and AJM's. No matter what I do it just won't let me send SMS/MMS through Alltel. I can connect to the internet, make, receive calls, and all that good stuff. It just refuses outright to allow me to send SMS/MMS messages. Any suggestions as to what I'm doing wrong?