[CentOS] Centos 6 / Kickstart Using degraded mdadm RAID1

I'm trying to install a bunch of C6 involving initially degraded mdadm RAID 1

Anaconda refuses to let me create a RAID 1 array with only one member.

Based on some reading, it seems that I should be able to use kickstart
with the PRE scripts to do this. However, after trying for a couple of
hours, it doesn't seem that anaconda will allow it, it just boots the
created arrays. At best I end up with a list of softraid partitions
instead.

Am I trying the impossible or has anybody done this before and can
point to a resource how on this can be done?