asterisk users - Apr 2008 - Transfer BACK to CallManager over SIP trunk?

We have occasional problems with failed transfers. The PSTN call comes
into Cisco Call Manager, then to asterisk over a SIP trunk and then to
an asterisk controlled SIP phone. The SIP phone transfers back to a
CallManager controlled SCCP phone which sometimes fails.

Is there a wait to let CallManager handle the transfer instead of
asterisk? I have a feeling asterisk is handling the traffic even after
the call is transferred.