Thanks very much, Pawpcorn. On further testing, I find that utorrent works fine with SSL if I go direct to the tracker and don't use my proxy. However, when going through the proxy (Superchargemytorrent), it doesn't work. Utorrent can't seem to make a secure connection to the tracker going through the proxy.
Of course I do want to use the proxy, but wonder if this is just an inherent problem of using any proxy, or whether the one I use just doesn't offer that feature. It seems like it ought to work since all the proxy does is do IP and port translation. But maybe not.
Can you shed any light on this?
Also, I find that my utorrent build isn't quite the last one. I have 25130. I'll update to your 25302 and see if that makes any difference, but I doubt it will.