After helping another forum user with his problem, I realized that a "Case (4) > Only" option (as oposed to "Excep.") would be very useful in those situations where only certain words need to be affected by the "Case" settings (i.e. changing acronyms to uppercase).
It should work in the same way "Excep." does: a box where the user will add the word (or words, separated by colons).
Cheers,
Gabriel.