We have an ASA 5520. We are using one of the gig etherner ports to setup a vendor network. The ASA is providing the DHCP services for the vendor network. The port from the ASA is connected into a switch port on one of our core switchs. The vlan port assignment on the core switch is that of the guest network. All works well for wired clients, but wirless clients which use the same vendor vlan cannot get dhcp info from the ASA. We are using a Cisco WiSM as the management for our wireless infrastructure. The configuration looks good on both the ASA and the WiSM, we had Cisco verify this. Now if we replace the ASA with a little Linksys router, both the wired and wireless clients get dhcp addressing just fine.