There is a patch that I wrote (it is currently outdated!) at:
This patch creates (against version 1.1) an auth.log file, which logs
Radius username, Source Mac Address, and Source IP address to the log file
when a user successfully authenticates. When they unsuccessfully
authenticate, it does the same, except logs it as unsuccessful.
Is it possible to incorporate something like this into 1.2b7? Its a very
very simple patch, I know many people could use it. It could even be
incorporated as a hidden config option. Its just tedious for us to
continue to customize every new version, and it sounds like a good idea.