how do i get mask edit to show the canadian postal code??

Canadian Postal Code which is of the form: letter,number,letter space number,letter,number

i've tried
&#& #&#
$#$ #$#
C#C #C#C (this work alright, but it lets me enter all numbers??, it doesn't restrict to just letters, also i want to force uppercase for letter..?? HOW?? )

thanx a lot

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