[Serusers] Problems using avps in subst

Hello I am trying to change the Remote-Party-ID header of a forwarded call but have little luck. I found several examples on the net where avps are used inside a subst but when I try this the resulting Remote-Party-ID is wrong My code: avp_write("$ruri/username","s:calledno"); subst('/^Remote-Party-ID:(.*)>/Remote-Party-ID: <sip:$avp(calledno) user=phone>/ig'); The result: Remote-Party-ID: <sip:$avp(calledno) user=phone>;party=calling;screen=no;privacy=off. Anyone who can point me to the error? I use SER 0.9.6 Med vänliga hälsningar/Kind regards Roger Lewau