Getting A Built-In Or Custom Document Property

This macro will return the value of a custom or built-in document property.  If the property does not exist, and empty string is returned.
Public Function GetProperty(p As String)
Dim S As Variant

On Error Resume Next

S = ActiveWorkbook.CustomDocumentProperties(p)
If S <> "" Then
    GetProperty = S
    Exit Function
End If

On Error GoTo EndMacro
GetProperty = ActiveWorkbook.BuiltinDocumentProperties(p)
Exit Function

EndMacro:
GetProperty = ""

End Function