Rose,
I'm pressed for time today, but one option would be to use mapped content controls to store your metadata. Mapped CCs are bound to a data node in a customXMLPart that become part of the document. It is an easy step to then save the data as a text file:

Sub ScratchMacro()
Dim fso As Object
'A basic Word macro coded by Greg Maxey
'MsgBox ActiveDocument.CustomXMLParts(4).XML
Set fso = CreateObject("Scripting.FileSystemObject")
Dim oFile As Object
Set oFile = fso.CreateTextFile("C:\New File")
oFile.WriteLine ActiveDocument.CustomXMLParts(1).XML
oFile.Close
Set fso = Nothing
Set oFile = Nothing
lbl_Exit:
Exit Sub
End Sub

__________________
Greg Maxey
Please visit my web site at http://www.gregmaxey.com/