Hotspot snmp problem

Hello, A couple of us at work have been playing with a hotspot controller (Internet Subscriber Server II ISS-4000) using freeradius and mysql for authentication. We are having problems with checkrad (totally to do with the AP not being nice). I'm not sure what is the best way to handle this. I can snmpwalk the device however the output does not appear to have information regarding logins. The manufacturer does not respond to queries so I'm hoping someone else may have worked with this device. Any help is appreciated, Robin