Here's my situation. I had an iPhone 4 w/ Orange Dominicana. I have a 3G unlimited data plan, etc... and everything working fine. My phone got wet and had water damage and ceased to function. So, I was in the U.S. this weekend and picked up a used 3GS. It was locked and had a 5.16 baseband. So i proceeded to upgrade the baseband to 6.15 and jailbreak it, then unlocked it. It is now working fine, but on EDGE... I can not get it on to work with 3G for the life of me. Any help? Any thoughts? Any advice?

*I'm still using my microsim that was used in my iPhone 4, just put an adapter on it.*