Cluster XL and non-routable addressing

[Pascal01]

Hi, I'm trying out following setup:

Hardware: 2 identical HP proliant servers with 8 eth. interfaces
OS: Splat R65
Interfaces are bond together per two and per interface bonding subbond interfaces are created with IP's configured on them.
Cluster setup is active/passive.

Management, firewall sync and the internet interface are using a dedicated subnet on the cluster setup, so the same range for FW1, FW2 and cluster address.
For all other interfaces (around 8) the cluster address is the routable address and for both firewalls dummy addresses so non-routable are used.

Is anyone using a setup like this and does is work on Splat?
I've created the needed static routes on each firewall so they know which networks are behind the interfaces.
The non-routable addresses are also included in the group of local nets needed for anti-spoofing on the internal interfaces.

When testing the setup I can see my outgoing traffic is accepted but no traffic is returning so it doesn't work.