First, those are not caliper brakes. Those are Cantilever brakes.
This is a caliper brake:
http://www.danscomp.com/484009.php?cat=PARTS
Now to answer your question, no the brakes in your link will not work with 990 (U-Brake) mounts.
The pivot point on 990s (where the brake mounts to the frame) is above the rim. The pivot point on cantis & V-brakes are below the rim
-Bill