Problems with CleanInstall from Recovery

Hi.

I use the latest PD7 Version with a Full License. Today i updated my MB Air 2011 from Lion to Mountain Lion. Then i made a fresh install of PD7, registered it. Then i tried to install Mountain Lion from the Recovery Partition, but only the grey Desktop with the Apple Logo appeared. So i waited 30 Mins. But nothing happens!

When i try a real recovery everything works fine.

Can anyone please help me.

Thanx in advance.
Thomas