I have a third party VPN server and a PIX 506e that are going to have a site to site connection. The third party is called a Junxion box and has very limited settings. I have had the Junxion and the PIX Site to Site setup and working with no problems.
The problem is my pix needs to be behind the ASA 5510. As soon as put it behind the ASA it stops working. I have A static nat from external ip to interal ip of the PIX. I have AH, ESP, and 4500 open on the firwall pointing to the external address of the PIX.