[Users] avp+radius+accounting

Hello, We 'd like to prefix something depend on some kind of group membership of users. During radius authorization radius set an avp e.g SIP-AVP prefix:123 I 'd like to set Request-URI according to this avp, but prefix("$avp(prefix)") don't work the uri will be sip:$avp(prefix)12233@... :) as i read pseudo variables is only enabled in xlog and some avpops functions. How can i solve this problem, Another question about acc module loadmodule "acc.so" modparam("acc", "radius_flag", 3) modparam("acc", "radius_missed_flag", 4) route{ #... setflag(3); setflag(4) #... } don't send accounting messages to radius, i must use acc_rad_request? Thanks any help, Tamas