Mate, if you dont get a reply in half an hour you'll have to be patient. Most of us work for a living during the day and relax at night.
And we aren't paid to sit at our PCs, we do it for free and often just get shirty responses.....
Rant over, (Another gulp of my Merlot...)
The reason to put sleeving on the black wire is to show that it is really a live wire. Normally a black wire would be neutral, but in the switch that you have, the black wire is actually the switched live. The sleeving says "ITS LIVE" or "MAY BECOME LIVE!!"
Comms isnt strictly correct, as you have to old cable colours (red&black) your sleeving on the black wire should be red.