SSL VPN Rate Limit per User/IP

I have been searching DEV for an answer to no avail thus far...

Using F5 APM (Firepass)

I have approx 200-300 SSL VPN users connectiing at any one time from any IP address, and they all have unique usernames which is controlled via Radius Authentication.

I need to find a way to restrict each unique successful connection to a specific BW limit (Say 512Kbps for example).

Any suggestions would be appreciated.

Thanks in advance.