OK. In that case the following function will do that. The function is written to work as a user defined process with
http://www.gmayor.com/document_batch_processes.htm which will handle the folders/documents, or you can call it from your own document selection process.
Basically it replaces any (or no) header and footer with the autotext entries from the normal template called @header and @footer, that you said you have created.
If you use the batch processor, ensure that you test it first on a single document to ensure that the autotexts do indeed produce the required results, before processing all the documents in a folder.
Code:
Function MyHeader(oDoc As Document)
Dim oSection As Section
Dim oHeader As HeaderFooter
Dim oFooter As HeaderFooter
Dim strTemplate As String
Dim orng As Range
strTemplate = Application.Options.DefaultFilePath(wdUserTemplatesPath)
strTemplate = strTemplate & "\Normal.dotm"
On Error GoTo err_Handler
For Each oSection In oDoc.Sections
For Each oHeader In oSection.Headers
If oHeader.Exists Then
Set orng = oHeader.Range
orng.Text = ""
Application.Templates _
(strTemplate).AutoTextEntries("@header").Insert Where:=orng, _
RichText:=True
End If
Next oHeader
For Each oFooter In oSection.Footers
If oFooter.Exists Then
Set orng = oFooter.Range
orng.Text = ""
Application.Templates _
(strTemplate).AutoTextEntries("@footer").Insert Where:=orng, _
RichText:=True
End If
Next oFooter
Next oSection
MyHeader = True
lbl_Exit:
Exit Function
err_Handler:
MyHeader = False
Resume lbl_Exit
End Function