Macro for automatically adding filename without .doc

[RPM7]

I have a document that I would like to embed the filename into the header.
The first page of the document has a blank header & the second page has the same header as the remainder of the document.
I initially inserted the field [file name] with Uppercase but it included the ".doc" at the end which I would like to remove. I looked online and most sites say this can't be done. (Plus the field must be updated to take effect)


Instead is it possible to insert a macro that upon saving the file would create a text box in both headers with the filename and the last 4 letters omitted to remove the ".doc".

Does anyone know anything about this?
I'd appreciate any help at all. Thanks.