Decoding Speex or TrueSpeech Used By Yahoo Voice Chat

Hi All,
Is there anyone who has any idea about speex or truespeech information
used by Yahoo Voice Chat that its uses over SIP>RTP.
Yahoo claims to use DSP True Speech for Voice Chat, but when we
captured the data. It was found to be using speex.
This Speex doesn't seems to follow the header info, as per Speex over
RTP specification.

UDP Packets were received of 82 bytes with 12 Byte RTP Header and
remaining 70 bytes were of Speex. (or audio data)
Now howz that speex has been respresented is unknown. Can anybody help
me decoding that.

Thanks in advance
ILA