H.248 using RFC2833/RFC2198 and SRTP/MIKEY

Hello,

I start looking to H.248 protocol and studying what it can do and what can't.

I am not able to find any documents related to following topics/questions:

1) RFC2833/RFC2198
  - how the MGC can get RFC2833/RFC2198 capabilities from the MG? (used payload types, list of supported tones, ...)
  - how the MGC can put peer  RFC2833/RFC2198 capabilities to the MG termination?

2) SRTP/MIKEY
 - is there any document how to use MIKEY within H.248 to negotiate SRTP contexted between the MG and peer media endpoint ?(can be also H.248 MG but also any other kind of SRTP endpoint)

BTW I would prefer to use binary encoding of H.248 and if I understand it well it can not use SDP equivalent properties, is it right?

Thanks in advance for any hint.

Best regards,
  Tomas