how to make a viper led flash when armed

My girlfriend has an old Viper alarm/keyless installed in her car. I'm going to buy her a new alarm/keyless/remote start system, but her a-pillar already has a hole drilled for the outboard mounted red LED which flashes when the system is armed. Well Vipers newer higher-end models have the LED on the antenna. So I can obviously just leave the old LED mounted in the A-pillar or pull it out and just have a small hole in the A-pillar. But I was wondering if I could make is flash when armed just as it does already? I thought about wiring it to +12V constant and the ground-when-armed connection, but I believe this would just keep the LED solid when armed. Or is the flashing circuitry in the LED housing? Ideas?

Here's a google image of the LED I'm talking about http://www.hiroizm.co.jp/minkara_img/img2/install/3/00763.jpg (And why can't you edit on this forum!?!?)

Your correct, if you hook the led via 12v and GWA, it will just be solid. The only thing i can think of is to strip into the antenna wire and use the circuit from that. I'm not exactly what wires are in there but id imagine there is 12v, Ground, TX, RX, Ground pulse for programming switch, and 12v or ground for the LED.

With the antenna plugged into the new WORKING viper brain ,arm the system which will make the LED on the antenna blink ,now use a DMM and put the black lead to ground ,now take the red lead of the DMM and probe the wires of the antenna plug ,the wire you are looking for will show about 0.6 volts dc then jumps to about 3 volts in sequence with the blinking LED. Take that wire and connect it to the red wire of the LED you have mounted on the car and the other wire of the LED goes to ground and that's it both LED's should blink at the same rate when the system is armed . Be careful when stripping the antenna and good luck .triniforever

Bah. I'm not risking that. Those antenna wires have an outer jacket that would have to be carefully removed, then carefully splice into those tiny 28awg wires. No thanks. I'll just have it stay on solid. lol Thanks for the input guys. Also just to add on, the Viper systems with the LED on the antenna also have the valet button on the antenna. So there's probably more than 4 wires in there. Or at least some sort of data multiplex going on...

The process I described to you took me all of ten minutes to do about a week ago !triniforever

haha Thanks.