802.1x dinamic vlan, using AD information

[Hegedus Gabor]

Hi all, I have a question.

I use this combination:
cisco 2950 sw as NAS
freeRadius 2.1.1 as authenticator,
Active Directory as the database,
and the win xp client.

It wokrs fine. I want one more thing, witch is dynamic vlan assignment.
How can I implement it?

My idea is enlarge the AD schema with vlanids and get it with freeradius 
and send to the switch.
Is it good? or have an easier better way.

I think somebody has met this problem, please tell me the solutions.

Thank you.
Gabor