Sync appears to work now with BingoDisk and HTTPS. I have not verified that the actual synchronization works between two machines yet, but the files are now written to the WebDAV server. Thanks for the workaround.
I have also notified BingoDisk's parent Joyent tech support about their issue, and they said that they would check into it and get back to me. I'll post an update when there is one.
I have also notified BingoDisk's parent Joyent tech support about their issue, and they said that they would check into it and get back to me. I'll post an update when there is one.