ActiveX

I have created an ActiveX control in VB 6 which has an event as below

Public Event evtTone(ByVal vstrTone As String)

The name of the ActiveX control is DTMFDecoder

In the windows form I reference the DTMFDecoder ActiveX and rename it to DTMF
The procedure below becomes available

Is there anything wrong with these parameter? i.e should there be the underscores?
In the below procedure can I use something like console.writeline(AxDTMFDecoder.__ctlDTMFDecoder_evtToneEvent) so that I can see what vstrTone is being passed?

Private Sub DTMF_evtTone(ByVal sender As Object, ByVal e As AxDTMFDecoder.__ctlDTMFDecoder_evtToneEvent) Handles DTMF.evtTone

End Sub

You can use this Convension (dim __myvar as string) just like
(dim myvar as string)