Reinstall broken system keeping data on a RAID1 system

[oxy]

Hi,

I wanna reinstall my ubuntu 12.04. It runs on a RAID1 on
two identical HDs completely mirrored, including swap.

It was broken after an update with update-manager
last week. (see thread "login window disapears after sys update").

When i boot the install-CD it recognizes the partitions on the disks
but doesnt see them as a raid. So if i reconfigure a raid as in the
first installation and install the system, can i somehow keep the
home data?

(pls dont ask why i just dont copy the data :-)

Thx