Finally, I got it working.
Its quite easy with these two Tutorials:
http://wiki.ip-phone-forum.de/telefone:snom:konfiguration?&#mass_deployment_-_schritt_fuer_schritt
But Things you should really know about:
- If you use an Unix TFTP Server for autoprov. do write the Filename of your phonesettings which does contains your Phones MAC in UPPER LETTERS!... i.e. settings-0023456700AE - otherwise it could fail
- Set right permissions for your settings
And if you would love to upgrade your Snom 360 Phones to Firmware 8, upgrade it from 6 to 6.5, 6.5 to 7 and from 7 to 8.