SSL VPN Tunnel mode Remote Network behind other Fortigate

Hi All

May someone can help me.

I have the following Situation: 2 Fortigate Clusters with 200D OS 5.2

One  Cluster (Cluster 1) Terminate only VPN Site to site Tunnels and MPLS Networks etc.

The Other Cluster (Cluster 2)is for DMZ and Inet Access.

So my Problem is that i want to reach  a Network with Remote Access (SSL VPN Tunnel mode) Remote User connected to Cluster 2    --------one Network wich is Behind Cluster 1.

All Networks which are directly connected to Cluster 2 are Reachable as expected. Also Networks which are behinde one Core Switch are not a Problem as Long the Default Gateway for the core Point to Cluster 2.

However the Networks which are behind Cluster One are not reachable.

Please Help!

Regards

Gabriel