Sure it CAN work, but honestly, the drum kits in the Tyros are about as good a sound as you will ever hear live, and no UNmic'd kit at normal volume will sound as good.

The basic tone of the drums is what impressed me most about the Tyros - it'd be a shame to loose that. Add some "gingerbread" and sizzle, but don't loose the "meat & Potatoes !"