following menu, scroll to your first disk and hit enter: the partitionier asks you, if you want to cre... downwards over the line with "FREE SPACE" and hit enter.
# Create a partition with the size you nee... "Partition settings" menu, go to "Use as" and hit enter.
# Change the type to "physical volume for ... ed for RAID use.
# Now look at the first menu entry in the partitioner menu, there is a new line:
