[SR-Users] Kamailio + rtpproxy + SRTP

I have some problem with SSL+rtpproxy, kamailio successfully decodes SIP, rtpproxy decodes SRTP frames, all is going to freeswitch unencrypted. FS transfers the call back, the call is going unencrypted though kamailio, kamailio encodes to SSL, but rtpproxy DOESN'T encodes RTP frames to SRTP. Hence, endpoint SIP equipment rejects the call with 488 Not Acceptable Here

Scenario

1. Endpoint device -> SRTP -> kamailio -> RTP -> freeswitch 2. Freeswitch calls back 3. freeswitch -> RTP -> kamailio -> PROBLEM (SIP[TLS] + RTP (but not SRTP)) -> Endpoint device 4. Endpoint device -> 488 Not Acceptable Here -> Kamailio

Could somebody point me what's wrong here?

Thanks!