You should try to head over to Howard Forums under Ryan's Wap and Cab with Cricket. Here is one of the threads he posted on to help you with wap and mms. Works like a charm! (read the info Ryan posted and his wap/mms cab is on there also)... And if your "text" doesn't work, call Cricket and ask them to refresh your settings!...Hopefully that helps!
http://howardforums.com/showthread.p...5&page=2&pp=15
By the way I have a cricket Htc Diamond also..