I've been tweaking the tests in FBDatabaseMetaData to actually test
getProcedures and getProcedureColumns (David Jenks told me to, I
swear). I found some glitches in the tested functions, and one nasty
bug in handling of null fields. I've posted 3 bugs to sourceforge
(bugs 599988, 599990, and 599992). As I can't actually post any of
my patches to cvs, someone else needs to review the provided patches
(attached to the bugs) and post them for me.
The null handling bug is probably the most pressing, as well as the
shortest patch, (even though it took me forever to find it). Common
symtoms for this bug would include NullPointerExceptions and
non-null fields being reported as NULL, but only sometimes.

Jeremy Williams