Michael:
I think I understand. Here are two simpler ways to accomplish this.
Bookmarks: Create a piece of dummy text in the header, select it, click
Insert > Bookmark and enter a bookmark name (must be one contiguous string),
and then click Add.
Your programmer would access the text in that bookmark with a statement like
MsgBox ActiveDocument.Bookmarks("BearTest").Range.Text
There are methods for changing the content of the bookmark, and that's what
the programmer would use. It's in the VBA Help.
Document Properties: Use a built-in document property, or use the Custom tab
of the File > Properties dialog box to create a custom document property.
Make it Text type, enter a dummy initial value, and click Add.
In your header, click Insert > Field. In the Field Names list, select
DocProperty. Click Options, select your new custom property, then click Add
to Field. Click OK to close all the dialog boxes. Your programmer will set
the value of this document property, then update the fields in the headers
and footers.
MsgBox ActiveDocument.CustomDocumentProperties("BearTest").Value
Again, these objects and their properties and methods are in the VBA Help.
You can also check this list for examples of code that will update all fields
in all headers and footers for the document.
Bear