G711fb to T.38 transcoding issue, anybody else?

Hello everybody,

We are trying to setup a transcoding scenario:

An incoming INVITE arrives from the PSTN to the SBC, the SBC sends an INVITE to our Centrex platform, which relays to the UAC (a Cisco SPA122, with a physical fax device connected to one of its line).

The call is answered, fax tones are exchanged and the SPA122 re-INVITE using T.38 codec (media of type image in the SDP).

As our PSTN provider doesn't support T.38, we have set codec-policies so that T.38 is (should be) transcoded to PCMA using G711fb policy.

On the signaling part, everything is fine.