[Serusers] RFC3261 transaction matching failed

[Mimmus]

Forwarding a call from Asterisk to Microsoft Live Communication Server 2005 
via SER (to translate from UDP to TCP), I get a 'one-way' communication 
(WMessenger user can hear voice but PSTN phone user cannot).
Running SER in debug mode, I found:
 DEBUG: RFC3261 transaction matching failed
 DEBUG: t_lookup_request: no transaction found

Searching Google, I found that this is a known bug in Asterisk.
I upgraded to 1.0.7 (Debian unstable) but bug is still present.

Peraphs, Asterisk mailing-list would be a better choice for this message but 
anyway can someone confirm this?

Thanks
Domenico Viggiani