LSMSSP.DLL error - ZCO 8.0.3, Outlook 2010, on Windows 8 running in Bootcamp

I know everyone is going to shout "unsupported", but the MD of a client just bought a MacBook air and told me to make it work with his Outlook, so with no Mac Outlook integration available I've stuck windows on the machine via bootcamp.

However, I'm getting the old and previously shouted about LSMSSP.DLL error when trying to configure an Outlook profile. None of the Outlook 2010/Win8 ZCO 8.0.3 clients on native windows are having any trouble...

Has anyone else had this error on the new connector and Zimbra 8? Is anyone running the same setup with it working? Our Zimbra is hosted by an external provider so not too much I can do to investigate...