missing drives with setupstorage?

[Andreas Schockenhoff]

Hi,

my RAID/LVM setup-storage config  works fine with Lenny. 

But I will not always use two drives during install. So I wonder 
how can I use the missing feature for the raid: 

Syntax from fai-wiki:
http://faiwiki.informatik.uni-koeln.de/index.php/Setup-storage

raid0        -    disk2.2,sdc1,sde1:spare:missing  ext2       default

I want install with one or two disks drives so I try: 

raid1        -       sda5,sdb5:missing     -        default

but it breaks. Is this syntax correct or not?

Also I wonder what disk2.2 say. 

bye Andreas