[ubuntu] kvm ubuntu boot problems

We use Ubuntu for a product we currently sell. It's Ubuntu 10.10 server and we build a new kernel for our software. It all runs with no problem.

We would like to make a virtual ubuntu system running on a CentOS 6.3 system for one of our customers.

Now for the problem. I have install CentOS on a server and created a Ubuntu vm using 10.10 server and KVM. All works fine. When I go to install our software and new kernel it fails to boot. I get this error:

Give up waiting for root device. Common problem
- Boot args (cat /proc/cmdline)
Check root delay= (did the system wait long enough? )
Check root= (did the system wait for the right device?)
-Missing modules (cat /proc/modules: ls /dev)
Alert! "/dev/mapper/xxxxxxxxxxxxx-root does not exist. Dropping to a shell

Remember this is virtual system. The initial load works just fine. The kernel I am loading works just fine on a real system.

If I go the the generic kernel that works there is a /dev/dm-0 /dev/dm-1 /dev/mapper/(three files here) but on the boot of the new kernel there is no /dev/dm-0 /dev/dm-1 or anything under /dev/mappers.

Any information on the would be very helpful.
Thank you.