Thanks for helping...
I agree, the phone *should* use SP1 for all call transfers, but it only does this for outbound calls, which are already using SP1 (GV). For an inbound call, which is using SP2 (Callcentric), when I hit transfer, the dialtone comes from SP2. If I type a number for transfer I get a warning from Callcentric telling me I don't have any call minutes available.
To force it to use SP1, after hitting Transfer I push the SP1 button on the phone, type a number, and the transfer works.
I have not made any DigitMap or OutboundCallRoute configuration changes; no OBi Expert changes at all so far.
When I check IP Phone -> Phone Settings -> PrimaryLine it is set to "SP1 Service"