I haven't bought my angel eyes yet, but as far as I know, they use ballasts. That means they have to charge, and don't turn on instantaneously. I think there's a slight delay, so I'm not sure you could 'pulse' them with the alarm. Or maybe I'm wrong.
What you can do, and what I'm gonna do, is wire them up so they turn on using an accessory button on the alarm remote, completely independent of the parking light circuit. It'll be a few weeks yet, but I'll post a DIY once I get them.