[Users] No Master Storage Domain added

Hi All, I have some strange issue at the moment after clearing my installation and did a new egine-setup. When I want to attach a data-domain to a datacenter I always get the message that I need to activate my Master Storage Domain, but it isn't there. As far as I know this Master Storage domain was the first added Storage Domain that becomes Master automaticly, but after a lot of tries and re-tries I need some help. Of course I have checked my logs but there is nothing to find yet Any idea what I do wrong ? Cheers,