Minimal config to get it working with FPL:
ITSP Profile X->ProxyServer =
voip.freephoneline.caITSP Profile X->RegistrarServer =
voip.freephoneline.caVoice Services->SPX Service->SIP Credentials->AuthUserName = 15145551234 (Whatever)
Voice Services->SPX Service->SIP Credentials->AuthPassword = Whatever
Make certain that are different for each SP (A or B)
Voice Services->SPX Service->X_ServProvProfile