Excel Function prototype popup box when typing formulas containingUDFs
 

Whenever a user enters a standard Excel formula into a cell (e.g.,
"=VLOOKUP(", then as soon as the user hits the "(", a yellow popup box
listing the function name and arguments pops up. This functionality is
extremely helpful.

However, it does not popup with UDF. Is there anything i can do to
change this? Even a gross hack would be perfectly acceptable.

Any help would be appreciated.