[Johnny Myers]

The easiest way I figured out (just now) Is to:

1. create a small new shape on top of the transparent shape
2. Select the newly created shape and the transparent one.
3. Use the Unite tool in the Pathfinder window to unite the transparent and opaque shape.

The transparent shape should become opaque, adopting the transparency setting of the shape
above it that you united with it.

shazam suckas