SetCustomData

Sub SetCustomData(doc, key, value)
    On Error GoTo ErrorHandler
    If value = "" Then
        doc.SummaryInfo.GetCustomByKey key, value
    Else
        doc.SummaryInfo.SetCustomByKey key, value
    End If

    Exit Sub
ErrorHandler:
    doc.SummaryInfo.AddCustomInfo key, value
    Resume Next
End Sub