Hi, I'm having a problem with a Sipura, it is sending for the G729 the tag "G729a" witch is not correct due the RFC. Media Attribute (a): rtpmap:18 G729a/8000 FS is returning (200OK) Media Attribute (a): rtpmap:96 G729/8000 I think that the problem is that FS is not matching the codec, so it returns the first dynamic payload which is 96. I think that I've seen post with a similar issue, and the solution was to change the tag before it hit the switch, so, what I've done is to change the "switch_r_sdp" (I have the rest of the parameters correct due I also use it to dynamically change the codecs order) and it's changing the SDP, but when FS sends the 200OK it is returning to the endpoint: Media Attribute (a): rtpmap:96 G729/8000 Which is exactly the same problem that I have without the transformation of the SDP. Is it correct? Do I have another solution? Thanks