Aux port Help for back to back routers

[<ccie2002@xxxxxxxxxxxxx>]

Hello:

I am trying to do the internetwork expert labs and due to 
some hardware limitions on my router I do not have
enough WAN links to do one of the labs. What I would
like to do is create a WAN link between two routers
thru the aux port.

I would like to know if this is possible. I have
tried a few configs and I can not get it to work.
The ideal goal is to use the aux port for an extra
link between two routers. Does anyone have any
configs that would work for this situation.

I am looking for the basic configs. I have
searched Cisco web site but I can not get
anyone of them to work.