Change Input Mask via script

Is it possible to change the input mask of an edit field via a script?

That property is not listed in the help file. Basically what I want to do is changed the mask as characters are entered because we have two ranges of serial numbers. The format is either ??????-????????-????? or ??????-?????????-?????. The first range starts with 10 and has 8 digits in the second block and the second range starts with 15 and has 9 digits in the second block.

Thanks for any assistance.
Ady.