I honestly have little experience in VPN Networking so this may or may
not be a very complex question.

Problem: I need remote users to VPN into our network and have access
to the web based application that is on another VPN connection to the
same router.

Over the past few months I have been trying to accomplish this goal
using many methods, none of which seem to work. I know this can be
accomplished because others (our competition) have done this.

We work for a contracting company that allows us 1 VPN connection to
their network in order to run a web based application that we need
pretty much every minute of every day. They have this VPN set on a key
negotiation of 86400 for phase 1 and 2. This limits the amount of
routers that allow this configuration. I have tried using the highest
end Linksys Router and SmoothWall. Neither of these allow for a 86400
timeout on phase 2 and thus will not connect properly. I am stuck
using a cheap Linksys BEFSX41 to connect.

I have tried the following:
-VPNing directly into our Linksys BEFSX41 router.
We are unable to connect to the other VPN web based application.
-Setting up SmoothWall behind the Linksys BEFSX41 router.
I was unable to connect using a L2TP connection (It seems you cannot
have this linksys router forward the ports properly, I even tried
DMZing the SmoothWall and could not connect)
-Trying to use more advanced routers so I can forward L2TP connections properly.
This did not work because the higher end linksys products and
Smoothwall do not allow phase to timeout at 86400 seconds.

My next theory is to purchase a Cisco 871 router which I hope will
allow me to set phase 2 at 86400 seconds and allow me to forward/DMZ
the appropiate ports to establish a L2TP connection to a router behind
it which will make the users appear to be "on the network" so they can
access the web based application.

I currently have the Linksys BEFSX41 router and a Windows 2003 server
at my disposal. I am ready to buy the products (within reason) I need
in order to make this happen.

Any ideas would be great.