Would it be acceptable to convert the spaces, as they are entered, to another character, and then process the textbox value on valid or lost focus?

Let's say you convert spaces to underscores, then in KeyPress:

if nKeyCode=32
	dodefault(95, nShiftAltCtrl)
	nodefault
endif

and in LostFocus:

thisform.locteValue = strtran(alltrim(textBox.value),chr(95),' ')