I have "Page X of Y" in a header where Y is normally a field of type
wdFieldNumPages. I have modified this field manually by inserting an
expression field (i.e. type wdFieldExpression) that reads "= expression - 3"
where expression in this case is the NumPages field. This works as intended
and I can create this manually. I need to create it programmatically however
because the -3 could be -1 or -2, etc. I cannot find any documentation on how
to specifiy the expression when creating a field of this type. Also, when I
look this field I created manually from the locals window in a macro, I can
see that the NUMPAGES field is contained within the expression field.
Does anyone have any idea how I can do this programmatically?

Thanks!