Has anyone managed to setup dynamic vlan management?

I am really struggling to the switch to communication with the radius server.

In a nut shell i would like to dynamically assign vlans based on several variables.

In this case i would just like to assign a vlan based on group membership.

If anyone has achieved this and would like to share the steps i would greatly appreciate it.

So far

I have added the server role and created a NAP to auto assign a VLAN(VLAN 20)
I have added all primary auth servers to the switch including the accounting server IP

In the summary is says that there have been no errors and no success so im assuming its not even attempting.

Any help would be really apprecited.

Thanks

Liam