Logging in to iCal server from Windows system

Hi

I'm trying to log in to our iCal server from a windows machine to connect an application to our iCal server.

Using the address https://our.ical.server.com:8443/calendars/users/myuser/calendar in a webbrowser, from Firefox it works fine, but from Internet Explorer or Chrome it doesn't work, and from our specific system it doesn't work either. We see 401 Not authorized errors in the log. Same problem with the non-ssl site (:8008), so it's not a certificate error

Are there any settings I need to configure on the iCal server for authentication from a windows domain to work?

Authentication is set to Any method.

Thanks!