We have a scenario with a PAP2T ATA registering as a SIP device to a UC560. Plugged into the PAP2T are some Kirk 4040 DECT handsets. Calls to and from the handsets work fine, but the 'R' (Recall) button used to place a call on hold does not work. The other end of the call can here a tone when the button is pressed but nothing happens. The voice register pool on the UC560 is set to dtmf-relay rtp-nte (i.e. RFC2833), inline with this document on the SPA8000 - https://supportforums.cisco.com/docs/DOC-9596.
Can anyone suggest any settings on the PAP2T to get this working please?