I used this
as a template for mine. I believe it's for 1.3.8, so the code is a little different in 1.3.9, the version I'm using. I haven't had much time the last few days to work on mine, so it remains as is. As my above post says, it's on my development computer, so I'm not under any pressure to get it done. If - actually - WHEN I get it all sorted out, I'll post what I did here.