Serial port pins as GPIO

I use a Fastrack Supreme 10 in a project and just need on GPIO in and one out. Using the GPIO pins on the power connector is not an option due to highly complicated (and expensive) cable assembly. Therefore I want to use some of the serial handshake signal pins for this purpose, controlled by an OpenAT application.

Is it possible?
Any hints on how?


BTW I know about the IESM IO Board, but using it would drive the target price through the roof.