[vpn-help] Problem connecting to Netgear SRX5308

[Shad L. Lords]

Problem:

I'm trying to establish a IPSec VPN to a Netgear SRX5308 with the Shrew 
Soft VPN Client. I've got it configured correctly to do mode config and 
xauth. If I point the exact same configuration at my Netgear FVX538 or 
Netgear FVS336G (also setup the same as the SRX5308) it connects just 
fine. However on the SRX5308 I get a "invalid message from gateway" 
message on the VPN client.  I've tried using the 3.0.6-9.1 firmware as 
well as the beta 3.0.7-11.1 firmware.  They both behave the same way.

VPN Client Version = 2.1.7 and 2.2.0-alpha10
Windows OS Version = Windows 7 Ultimate (32-bit and 64-bit)
Gateway Make/Model = Netgear SRX5308 (broken)
Gateway OS Version = 3.0.6-9.1 and 3.0.7-11.1 (beta)

Gateway Make/Model = Netgear FVX538 and FVS336G (working)
Gateway OS Version = 3.0.6-29

In comparing the IKE decrypted packed dumps between the FVS336G and the 
SRX5308 they are the same up to the point of doing the mode config 
negotiation. The FVS336G does a ISAKMP_CFG_REQUEST (1) and receives a 
ISAKMP_CFG_REPLY (2) with all the data needed (ip, mask, dns, etc). The 
SRX5308 does the same ISAKMP_CFG_REQUEST (1) and receives a 
ISAKMP_CFG_SET (3) with the needed information (ip, mask, dns, etc). 
Because the packet is a SET instead of a REPLY the client doesn't 
recognize the packet as one it expects and fails to bring up the tunnel.

I've got packet captures of both firewalls that I can send if necessary.