Cingular ROM for 5600?

[Guest bonsai]

i have an unlocked cingular blue (attw) smt5600 and i noticed that the network preferences and settings are unchangeable from the att defaults. this makes my phone lock onto the 'att' network even though the att network should be the same as the cingular network. this causes my phone to think it is roaming and thus display the little roaming triangle.

1. i need a cingular rom to make my phone lock onto the 'cingular' network

2. will the cingular rom remove the roaming icon? (i have read a thread on this board about how the triangle is still present with a cingular rom...is this an anomoly?)

TIA