[Serusers] Accounting: Logging to radius if user isn't in userloc or unavailable

[Alan]

I would like the accounting module to write information in the mysql db
through radius if a user isn't registered in the location database. I
believe the SIP response code is 480 (Temporarily Unavailable). 

Currently I am writing successful and missed calls from ser to radius. Can
this be accomplished without modifying the sources? Please help.

~Alan