VPN Client Passthrough

[Linuxian]

I am trying to set up a test environment using my guest network which
consists of a CP firewall on an isolated (guest) network.

Design:
1. There are two firewalls at my site. One is for the guest network,
the other is for the main production network.
2. Each firewall has it's own independent ISP WAN link.
3. Each firewall is part of the same management domain (Both are
managed by the same SC Server)

What I want to do:
I want to test a Secure Client by connecting it from within the guest
network to the main firewall.

Problem:
1. The guest-network firewall is allowing IKE traffic to pass to the
target firewall. - no problem there.
2. The target firewall initially accepts the IKE request then responds
with the following log entry:

Encryption Scheme: IKE
Information: IKE: No common community for myself and
peer

Anyone have any suggestions?