Yes, I've done so. But mine (2001 2.7) had the stock alarm system with remote included. I had only one transmitter and wanted to add a common aftermarket remote unit to it so now it can lock/unlock without enabling the alarm sys - and add additional remotes if needed.
The installation I've done includes removing the ETACS, opening it and soldering some wires in there. In addition it has a separate trunk release hardware now (was needed because the original servo at the tailgate was broken - something melted inside - and did only lock but never unlock the rear end).
I can only assume that you have a simplified version of the ETACS (maybe ETCS - without A which stands for 'alarm') installed - since it also controlles other things like interior lighting etc.
Basically the task is simple: two of the pins on the unit get grounded (not the same time of course), one for lock and one for unlock. Connector A, pin 14 for lock, pin 20 for unlock.