You may want to see if a vlan is necessary on your network, specifically if you are running VoIP.
With a 1200 series Ap, all you have to do is configure the ssid as authentication open on the unsecured, and add the security to the other ssid.
This is what I have ...
dot11 ssid secured
authentication open eap eap_methods
authentication network-eap eap_methods
accounting acct_methods
!
dot11 ssid unsecured
authentication open
infrastructure-ssid optional
!
interface Dot11Radio0
no ip address
no ip route-cache
!
encryption mode wep mandatory
!
broadcast-key change 10800
!
!
ssid secured
!
ssid unsecured
!
Hope this helps.
I have done this for AP1200s, but not 1100s.
