I finally got some spare time to work on this and got this working.
The software that will do this is etherpuppet.
The developer has both a regular linux version that can be used in backtrack and a linksys router version that can be run on the router.
By installing Etherpuppet on the linksys router, you can send all traffic from a chosen interface to a remote workstation so that it can be manipulated and sent back.
SSL strip worked fine on the traffic on both of my DD-WRT routers.
And so did any other program that I tried, for example metasploit.
I used the br0:0 interface on the router
However I tried another a couple of other DD-WRT routers (older ones), which did not have the br0:0 interface, and etherpuppet could not keep the connection. Could have something to do with the older version of DD-WRT or it could just be the different chipset. Mine are the Asus PN16 and WGL
I am still trying to figure out how to start an br0:0 interface or what interface besides br0:0 will work on these other routers as I had no problem running etherpuppet on them.
Also etterpuppet works great connecting two workstations this way.
I am not sure why it is not included in backtrack considering it is such a useful tool!
Sample command lines:
On linksys router:
etterpuppet -s 888 -i br0:0
# This makes the br0:0 interface available on port 888 for any computer to connect and use.
etterpuppet -c 192.168.0.xxx:888 -m -I myinterface
# This tells it to connect to an IP address and port number in master mode and create a new interface.
remember to use ifconfig myinterface up
to bring up your new interace
just rename etherpuppet-mipsel to anything, upload it to you router (chmod 777) and run it.
For the linux version, you need to compile it for backtrack, which is really easy and instructions are on the website
Better just to get a better router with more ram. I am using the Asus N16 with 128 MB Ram, USB and a faster CPU. There may be some newer ones out there.
Sorry, this is a double post please delete