Quick Light Flash

Hi, I'm sure many of you have probably seen the newer vehicles that have the parking lights flash fairly quickly when you lock or unlock the vehicle. The newer Nissan vehicles come to mind. Anyway, I want to replicate something like this on my car. Currently, my lights flash slowly from my Autopage alarm, so using the alarm's parking light output and a relay probably isn't an option, since, even if I could somehow minimize the length of the parking light flash, the two flashes on unlock would be fast, but with a long gap in between them. So here was what I was thinking so far. Buy a hazard flasher relay from my local auto parts store, and open it up, then replace the capacitor or resistor inside of it to make it flash faster. Then, I would use a relay on my siren output, that would send +12volts to the hazard flasher when the siren output is triggered. The hazard flasher would then have a wire with a blocking diode going to my parking light circuit. I've just got a couple quick questions before I go about attempting this. 1. On the hazard relay, would I want to replace the capacitor or the resistor, or both? Could I just replace the resistor with a pot so that I could alter the length of the light flash? 2. On the siren, output, on unlock it only gives on chirp. On lock, it gives two. Does the siren provide one short +12volt pulse for each chirp? Or does it provide a longer +12volt pulse for the unlock chirps, and a shorter pulse for the lock chirp? Or are the pulses not even +12volts?

Bump.