[Serusers] alias/rpid instead of subscriber in acc

I am using acc table for accounting of INVITE, BYE and CANCEL. This info is then used to create CDRs for billing. It works great with one exception. My setup is that every subsbriber account is tied to a public PSTN number. The PSTN number is set in the rpid field of subscriber table as well as stored as an alias for the subscriber account. On every call bound for pstn, I add the rpid header to provide CID for the B end of the call. Now to the strange part. I have some asterisk servers registered as ua in SER, when these servers make calls some calls get registered with a from uri that are equal to the SER account used, some calls are registered with the PSTN number as the from uri. Two consecutive calls from the same asterisk box and user to the same pstn number, can produce one of each from uri. The way I like it to be is that all calls should be registered with the SER account used. This only happens with asterisk as ua. At first, I though this could be because I set asteriskt to canreinvite=yes, but same thing happened with canreinvite=no. When is a record actually saved in acc? Anyone with an idea why this inconsistancy occurs? Some code: extract from sip.conf ========== register => 1000:1234@sip.serverhallen.com/552000; incomming [ser-out] ;outgoing calls type=peer host=sip.serverhallen.com language=se username=1000 secret=1234 fromuser=1000 insecure=very context=vbx extract from extensions.conf ======================== exten => _X.,1,DIAL(SIP/${EXTEN}@ser-out,60) from ser.cfg main route block ===================== if (method=="INVITE" || method=="BYE" || method=="CANCEL") { # enable accounting for INVITE and BYE and CANCEL messages. setflag(2); };