it turned out that cisco ios sip implementation does not include the new
route uri parameters (ftag, lr) that cvs ser adds in its record route
entry in the requests (ack, bye, ...) that cisco sends within a dialog.
what i heard is that it may take until the end of the year until these
bugs get fixed.
thus there is even more reasons to push cisco to get their acts together
or find a better sip/pstn gw from some other vendor (so far i haven't
heard of any).
-- juha