How do we add our building (Shape)
data to MapPoint background?

We tried programming with
MapPoint's VB COM, but it dramatically slow
down the display when number of
buildings exceed 1000. Since we
have more than 3000 square mile
building data for USA, covering
12 US cities. I am wondering is
there any way to create MapPoint
proprietary data format so that
our building shapes can be displayed for our clients.

Thanks.
James