I have a couple of workarounds for the syncing between Lotus Journal and Palm Memo Pad via m Notes.
Option #1 - Create a category on your PDA in Memo Pad and make a test entry in that category. Perform a HotSync and the entry and its category will sync to the Journal in Lotus Notes.
Option #2 Create a category in your Notes Journal and make and entry then create exactly the same category on your Palm the Journal entry will sync to the correct category in Memo Pad on your Palm.
But for some reason categories created in the Lotus Journal alone willn ot sync...
So to fix your problem I'd just create the categories you need on your Palm and your existing Journal entries should sync nicely.