billing, reporting for Radius accounting logs

Hi,

I am looking for a software, freeware,tool, ,that can generate me
reports
for billing reasons to different lines of services.. based on the log
files
created by the radius accounting server.. xxxx.dat file.. in the
sys\etc\radius\acct directory.

Is anyone using such a software or point me where to find it..

Kind

Regards

Guido