Window Shatter Effect

Dear Cows,

I've created a simple countdown sequence from 10 seconds with large white numbers on a black background. It's to be used as part of the opening of an event on a big LED screen.

When the countdown reaches Zero I'd like it to smash to pieces like a window shattering. FCP7 and Motion 4 doesn't seem to have a shatter effect in its arsenal of presets, so can anyone suggest a work around for this or even a third party plug-in?

Many thanks,

Steve.