[Freeswitch-users] Codec negotiation with ESL socket?

Our current Polycom phones send the following in the SDP: a=rtpmap:0 PCMU/8000 a=rtpmap:8 PCMA/8000 a=rtpmap:18 G729/8000 We added a 550 phone and now the preferred coded is G722 *a=rtpmap:9 G722/8000* a=rtpmap:0 PCMU/8000 a=rtpmap:8 PCMA/8000 a=rtpmap:18 G729/8000 Our IVR application (socket) plays files recorded in PCMU format. When the new phone connects (G722), the play function is now looking for files ending in .G722 (which do not exist). How do you negotiate a codec without a B leg? I'd like the phone to use G722 when connected to other G722 phones, but use PCMU if connected to a socket application. Thank you, Ian.