User Authentication to Firewall

I have a 3COM superstack Firewall on my LAN and I’m looking for some software that I could maybe use to force User authentication to this firewall. The Firewall doesn’t allow for this and there is no way to force it using only the firewall. I contacted 3COM on this issue and they said it’s not possible with the Firewall alone, but that there might be some 3rd party software.

I need this to capture authenticated usernames for my monitoring software so we don’t have to go by IP addresses.Does anyone know of any software that could help me?

thanks,