Inter VDOM routing wireless traffic

[VWCVO]

Hello,

We have a Fortigate 100D, FortiOS 5.4. We have been trying to get a setup working, but so far unsuccesfully. The setup we are trying to achieve is the following:

URL to schematic

When we ping between a PC in LAN B and a laptop connected to SSID B, we have no connectivity.

When we check VDOM A (packet capture on fortigate), we see the packets coming in. A route lookup and a policy lookup give the correct results. We have policy based routing in place to bend the traffic to the correct interfaces, for each policy based route we have a corresponding static route. The same when we do those checks in VDOM B, everything appears fine (route lookup, policy lookup, packet capture). But although the route lookup gives us the correct route, the packet capture shows us that the packets are always routed tot the outside (to the ISP's). What are we overlooking (policy based routes have the same or lower distance than the default gateway distance, and the packets reach the other VDOM over the inter VDOM link, as we can verify with the packet capture.

Maybe this scenario is not possible?? Or are we overlooking something?