Problem solved
Create User "Guest" in the sap system (UME)
in the UME expert configuration (Identity Management => Konfiguration => Expert Modus) enter the new User "Guest" in the ume.login.guest_user.uniqueids in the first position (don't delete any user here).
Restart the system
After this configuration the sso Server 2.0 with sp6 patch 1 could create a new certificat for the sso client