Setting a Ghost 15 backup job for incremental backups

I know how to do it manually do an incremental backup after a full one was created by right clicking on the job and selecting "Run Backup With Options".  One should be able to set it permanently in the job settings to avoid the mistake of running the job normally thus creating a full backup again in the same folder.  Also, I like to use the trigger technique but can't as it would always produce a full backup too.  Is there a solution for this?