On at least Windows 7 x64 with the x64 installation and Windows 7 x86 with the x86 installation on the workbench when you try to enter a remote repository address with at least https, specifying a hostname with an '@' symbol (see format below) causes some unstable behavior.
In the workbench when you attempt to save it, it does not show in the paths panel. Sometimes it will (especially when you moved away from the sync screen then back) but it will be missing the username.
If you attempt to enter the address in the .hgrc under paths then when starting the workbench it will crash with an invalid String format exception.
It is possible to push and pull to the address however, but you constantly have to enter the username + password.