I don’t know if it matters, but VOIPo wants you to use the BYOD credentials supplied in your vPanel (getting it is convoluted—you need to go to Features, Preferences and BYOD). That said, while I don’t have Gingerbread, I understand it has a native SIP client like ICS, so you might want to try it—and configure it to use the BYOD server as a proxy—or try reconfiguring Sipdroid to use your BYOD credentials and proxy.