VBA to save word doc in new 2007 format?

[drichird]

Here is some old VBA code inside a Word 2003 document to open and then save a word document:

Documents.Open FileName:=docFileName, ConfirmConversions:=True, _
        ReadOnly:=False, AddToRecentFiles:=False, PasswordDocument:="", _
        PasswordTemplate:="", Revert:=False, WritePasswordDocument:="", _
        WritePasswordTemplate:="", Format:=wdOpenFormatAuto

       'do stuff to the opened file here...

        ActiveDocument.SaveAs _
             FileName:=docFileName, _
             FileFormat:=wdFormatDocument, _
             LockComments:=False, _
             Password:="", _
             AddToRecentFiles:=True, _
             WritePassword:="", _
             ReadOnlyRecommended:=False, _
             EmbedTrueTypeFonts:=False, _
             SaveNativePictureFormat:=False, _
             SaveFormsData:=False, _
            SaveAsAOCELetter:=False

I ported the code to a word 2007 document, but now if I open a word 2007 doc the save code still saves it in the old format even if I specify a docx extension. What are the new parameters for FileFormat:= ..... now that MS is using the new open XML format. Can I save as either new/old format? Are there any other pitfalls to file I/O with the new MS open format?

Thanks ahead, for any help