How to ignore/clean/delete partitions on FAI installer?

[Norman Schmidt Jr]

Something I wasnt able to find out in FAI docs was how to ignore 
existing partitions when setup-storage runs.
I dont have any preserve<no> in my storage configuration files at 
config/disk_config/, but if the target disk for a FAI installation was 
previously partitioned, FAI stops the installation right at:

Executing: mdadm --examine --scan --verbose -c partitions
Cannot satisfy pre-depends for true: vgchange.........................
Error in task partition. Traceback: task_error task_partition task 
task_install task task_action task main
$LOGUSER is not defined...................
FATAL ERROR. Installation stopped.

I can solve this by deleting all target disk partitions using 
fdisk/cfdisk/sfdisk/dd'ing the MBR and rebooting the installation media, 
but how can I automate the cleaning of anything FAI may encounter at the 
target disk?

Thank you in advance,
Norman