Typically your RAID volumes will show up as /dev/mdXXX

If it is not, it could be because the device mapper module is not loaded.  Load it by running the following command.

modprobe dm-mod

As a side note you can list the block devices using

dmraid -b

https://bbs.archlinux.org/viewtopic.php?id=42321

If your still having trouble you can try installing mdadm and dmraid

apt-get install -y dmraid mdadm