ghost & saving mailboxes Exch5.5 rebuild

I need to add a larger hard drive to a server that runs Exchange 5.5. I plan on creating a ghost image of the server, installing the new HD, then install the image on the new drive.

In case the ghost image does not work, I need to import the mailboxes. That leads me to my next question, what do I need to save off the server in case I need to rebuild Exchange manually?

Thanks for your suggestions.