Audio Systems: 99 Accord Factory Alarm Problem when stereo replaced, pin wires, aftermarket stereo

Question
I just recently changed my double din factory stereo with flashing anti-theft light on my 1999 Honda Accord V6 to an aftermarket stereo.  The wiring was simple since the intall shop used a wiring harness, however my alarm now sounds after 2 minutes of being armed and untouched.  Tried replugging in the old stereo, and the alarm remains off...is it possible to put an aftermarket stereo  in this accord or am I stuck with the old stereo?

Answer
your vehicle is 99 but made in 98 so you have a 1998 Honda accord
the door pin wires go in to the radio and out of the radio
by removing the factory radio you open the circuit and it will trigger the alarm  
you need this
http://www.audiooutfitter.com/store/133147/701720t.html