How to get the x,y values(in pixel) via mapscript?

[Hermann-Marcus Behrens]

I'm using mapscript(with perl) to create maps on the fly. I add points  "by
hand" ($point->draw). Now i would like to enhance this application with
overlib.js, so a user might move his mouse-cursor over a point(drawed "by
hand" ;)) and an image would be displayed. For this feature i need the exact
points in pixel, where these points are on the final map. Any suggestions,
how to solve this problem?

Here you can see, how the application works:
http://www.citybeat.de/bremen/alles?adatum=2001-03-09&graum=bremen
If you are curious: citybeat is a town-portal for Bremen and Hamburg in
germany. The map is from official sites completly in TIFF. If you zoom in or
out, it will change (zooming out) to Vector-Data. If a mouse-cursor is over
a red dot, i would like to show a picture. I only need the coordinates, the
displaying is no problem.


Thank,
 Hermi