This doesn't appear to be supported in the 6.x product. You can only sync passwords if you enable SSO. The next best thing would be to figure out the problem between your SSO software and ours. We can usually sort this out with some registry trickery. Are you working with Windows XP or Windows 7?
I have both Systems, Windows XP and 7. I want to have the password synchronization between EE and Windows to make the user live easier, but I can't enable the SSO because I have another corporate solution to SSO, that integrate SO, Mail, Web Application and ERP.