RDM with more than 2TB LUN

Hi all,

we have a ESX4 environment with 4 Hosts. Now we have to buy new storage and I would like to add more than 2 TB Volumes to the Windows Server 2008 Guest.

As i remember this is not supported by ESX4.

1. SO i have to install a 5th host with ESX5 and add the new LUN(10TB)  as an RAW device in hardware modus, is it right so far?

2. We are on VMware Center 4 as well. SO my next question is it possible to add the ESXi 5 Host to my VMWARE Center 4?

3. If so, do i still can migrate the guests between the ESX4 and ESXi5 hosts?

Hope here are some pro's with such experience

Thanks.