Hi,
If you are setting up multiple VLAN's on the 1200 series access point, you need to assign a new SSID to each VLAN..
Eg,
SSID is Vlan1-A and is assigned to Vlan1
SSID is Vlan2-A and is assigned to Vlan2
After setting up the SSID's you need to ensure that you configure the Native Vlan, this is a drop down box on the same page. Set this to your normal management Vlan.
You also need to set the ports that are to be used by the access points on the switch to trunk ports, as follows;
interface fastethernet 0/1 {or select port required}
switchport trunk encapsulation dot1q
switchport trunk native vlan 1
switchport mode trunk
You also need to do this on the port used for the Cisco ACS server.
To enable users to access different Vlan's simply set their client card to access the SSID that is assigned to the Vlan that they want to use.
Hope this helps.
Many Thanks