How to log users in radutmp

Hi I have a rather simple freeradius server. I run freeradius 1.0.5 on solaris 10 with PEAP/MS-CHAPv2 authentication through the users file. I want to see who's connected with radwho, but when I run that I only get: # radwho Radwho: Error reading /usr/local/var/log/radius/radutmp: No such file or directory I don't have that radutmp file. How do I get freeradius to log users in that file? Regards, Torkel