samba - Nov 2012 - win7 client cannot join samba4 AD DC

I want to communicate my experience with samba4 version
4.1.0prel-GIT-1f55865.
System Fedora 17
I followed the samba 4 Howto
Download, configure, compile, install, provision work fine.
Server starts, DNS and Kerberos tests ok.
I can create test share, join it from server and linux client
Join of windows 7 client fails with error
'The specified network name is no longer available'
Any hints?

Regards J. Kuehner