Storing Guids in DB2/400

All,
 
We've got a need to store Guids in a DB2 table. At first we thought we
could use the RowID column type, but there can be only one of those on a
given table (makes sense). I guess we could use a char(16) to store it
in "native" format, or a char(36) to store it in character format
(7AF7EAA1-D035-4E22-BAD8-7F5640ECC4A7). My problem with using a char()
field is we could also store '*anything' in that field and the database
would be just fine with that. 
 
So, my question is, are we missing a datatype that will store Guids? And
if not, does anyone have a check() clause that will validate a Guid
before we store it in the database?
 
-Walden