multiply users download limit

[vocal]

Hello everyone.
First of all, thank you for all your great work.
I managed to set up all I wanted based on FAQ and HOWTOs
Im just having problem with setting up two different users with different download and upload.
I have 3 NICs, LAN, WAN and GUEST. Captive portal running on local database.
I have two users, STD and VIP.I have set up download and upload limit but it works for both users.
Any advise please?