We have Zimbra 5.0.0_RC1_1538.F7 FOSS version on Fedora 9

We have purchased a new RHE5 server and have downloaded zcs-NETWORK-5.0.9_GA_2533.RHEL5.20080815101705.

I need to place the mailboxes from the FOSS version to the new Network version and I need to maintain all the shared address books and calendars.

What is the best way to do this?

Can I just setup the new server and "restore" the mailboxes to it?

I can sense this is not going to be an easy project, but I can pray.