TextField Mask with Special Characters

I want to apply a mask to a TextField that only allows these characters:
<>,.-+;:_’*!#%&/()=?\[]{}$£@^|~"

Not sure if Xojo allows for this as I don’t see characters noted here or how to escape them into the mask:
http://documentation.xojo.com/index.php/TextEdit.Mask

Do I need to write a function that checks for these? Or is there a built in method.

create a routine in the KEYDOWN event
something along the lines of

return Instr("<>,.-+;:_'*!#%&/()=?\\[]{}$£@^|~"+chrb(8)+chrb(3)+chrb(13),key)>0

this should allow the characters you mentioned, plus [RETURN], [ENTER] and [BACKSPACE]

Thanks @Dave S !

Turned out I needed this:
return NOT (Instr("<>,.-+;:_’*!#%&/()=?\[]{}$£@^|~"+chrb(8)+chrb(3)+chrb(13),key)>0)

Thanks for the help!

Thats great, but what about this Character “`” Accents? what is the hex code of that, I mean in Keyboard Xojo docs are not available

“`”=0x60 or chrb(96)