My sprint TP can not forcing roam!

[lcy]

I am currently using Sprint Touch Pro with a SERO plan, but my apartment has bad signals, the tethering speed is awful, I was informed TP can be forced to roam on Verizon or some other fast local carrier, so I searched this forum and DIY myself according to
http://forum.ppcgeeks.com/showthread.php?t=38385

I changed the registry, and now I can found

Sprint Only
Automatic
Automatic-B

on my cell phone, and once I selected Automatic-B, the signal will turn off, showing sign of searching, but no picking up anything, I don't know what is the problem, can somebody help me out, thanks.