For instance, the following sample prints the last line in the first attachment:

With ibx(Index)
    Debug.Print .Line(.Attachment(0).LineTo)
End With

The following sample prints all lines in the attachment:

Dim msg As Message, i As Long
Set msg = ibx(Index)
With msg.Attachment(0)
    For i = .LineFrom To .LineTo
        Debug.Print msg.Line(i)
    Next
End With