expression.SaveNewWebPagesAsWebArchives
expression Required. An expression that returns a DefaultWebOptions object.
Remarks
Setting the SaveNewWebPagesAsWebArchives property won't change the format of any saved Web pages. To change their format, you must individually open them and then use the SaveAs method to set the Web page format.
Example
This example enables the SaveNewWebPagesAsWebArchives property so that when Web pages are saved, they are saved using the Single File Web Page format.
Sub SetWebOption()
Application.DefaultWebOptions _
.SaveNewWebPagesAsWebArchives = True
End Sub