Another UoM question

Apparently I am blind. I got a request to add dimensions by unit of measaure. The logical place to add this is PartUoM table, UD fields, except there aren't any? No UD Fields in the PartUOM table? Great. Now I have to do some elaborate cross-reference based on PARTUOM, including BPM's to make sure I don't miss an entry. Am I seeing this correctly? (Man, I didn't want to use a UD table for something like this...)
Thanks in advance for your help!
- leAnn