Regardless...it would be idisk.me.com/your-mm-name.
whether you use
https://, webdav://, or webdavs:// (as some use to force ssl) is dependent on the program itself.
If one doesn't work (https), try the others.
For example, using Finder it is
https://idisk.me.com/mm-name
on KDE (Linux/UNIX), it is webdavs://idisk.me.com/mm-name