DHCP to VLAN Wifi AP

I have pretty simple setup, yet can not make it work. Linksys WAP200 AP with two SSID (SSID1 for default Vlan1 & SSID7 for Guest Vlan7) It connects to a switch gig port in trunk mode Allied Telesis AT8000 which in turn connects to a core AT SBx908 via fibre port (also in trunk mode) Then one gig port from SBx908 (same trunk mode) connects to port 1 on FT 200B which is in Vdom1 AP ---> AT8000 ---> x908 ---> FT200B FT200 has 2 Vdoms (root & Vdom1). On Vdom1 there is DHCP server (on Interface Name port 1) If I connect to SSID1 I get the DHCP from FT200B from DHCP server on port1 (mostly - as sometimes I do get it from the mail LAN on root Vdom, strange!) If I connect to SSID7 I get NO IP at all How do I need to configure the DHCP on FT200B, so it gives me the IP for SSID7 (Vlan7)? Thanks Seb