YMMV, but this is how it works in Word 2002.
Right click in grey area below the top blue banner - select 'Customize',
then 'Commands' tab in the Customize box.
In left-hand window (Categories) select 'File'. Now in the main Word
window click 'File'. Drag one of the 'omnipage 12' lines into the
right-hand window (Commands) of the Customize box. Repeat for the other
line.