Change the mask to 999,999,999.99

>I have a text box with an InputMask like ###,###,##9.99.
>
>Trouble is: If I enter, say, 1234, it obeys the leftmost part of the mask and ends up being displayed as 123,4 - as much use as a one-legged man in a butt-kicking competition.
>
>I seem to recall, back in the legends of the Dream-time People, that this issue has been dealt with before and resolved with someone's fancy s/w.
>
>Any recollections?
>
>'ppreciate it.
>
>Terry