FW: customized format of log file

Hi all, I'm deploying a WiFi proxy center with FreeRadius now, therefore I need detailed auth/acct log records for statistical purpose. While default format of detail log cannot satisfy my goal there, so is there any way to define my own customized format of auth/acct log file? for example, for auth, I can write "AA" value while receiving "Access-Accept" and "AJ" for "Access-Reject" into log file. Another question, how to use "tab" as delimiter of logging instead of default ":" ? In general, my question is: Can anyone of modules process any content of packets without replacing and updating original attribute value by regex, unlang before output of logging? just for logging purpose. Or it's necessary to use Perl? Thanks in advance!