Bubble Graphs - Plot outside edge of bubble

[User (Legacy)]

I'm creating bubble charts in Chart FX 98 and want to place  annotation text 

on the top of each bubble. 

Does anyone know an easy way to calculate the X,Y location of the outside 

edge of individual bubbles?  (currently I'm calculating an X,Y coordiant 

that is a fixed percentage from the center of the bubble data point) 

Thanks, 

Michael Ryan