Microsoft has posted a fix to enable you to select RedHat as the OS of a VM in VMM 2008 R2, 2008 and 2007. Without the fix you get this error:
The virtualization software on host <server> does not support the Red Hat Enterprise Linux 5 operating system.
The problem is that the VMM database needs a tiny adjustment. You can do this easily enough using SQL Management Studio or SQL Management Studio Express. First, you should back up the database (don’t come crying to me if you didn’t!). You then need to create a new query with the following:
where Name like ‘Red Hat Enterprise Linux 5%’
Run the query and you should be sorted.