At the request of the 2nd level blackberry expert, I swapped my sim for my wife's (non-bb). Lo and behold, my Curve switched over to uma (albeit lowercase). This proves it isn't my router or phone, so I get to go back to the T-MO store tomorrow and get another new sim. Fingers crossed, but this should fix the issue.
Good thing I'm unemployed right now... I have plenty of time to run all over the place to get new sims.