thanks for the Information, that worked fine.
But we came across a different problem: Because the Backup to Tape takes some hours, the next planned endpoint backup (into the Veeam Backup Repository) was already started during the tape backup. This led to the tape backup being cancelled, because it could not access a file in the folder containing the endpoint backup.
Is there no way to organize those two concurrent backups? I know that the backup to tape can be delayed, if there is an endpoint backup which is still running, but the endpoint backup can probably not be delayed until the backup to tape has finished?