Migrating certificate services to Server 2008 R1

I am currently planning a move of an Active Directory Certificate Services CA from a soon to be decommissioned Server 2003 R2 Standard box to an existing Windows 2008 R1 Enterprise box.

This is not something I have done before, so I've been looking through relevant documentation to get an idea of what's required, before testing the process in a lab. The most reliable and complete source of information seems to be Microsoft's Active Directory Certificate Services Migration Guide. However, it only covers scenarios involving a destination server running the R2 release of Windows Server 2008, and not "R1".

Can anyone offer any advice on whether the guide can still be followed as-is or whether the approach needs to be modified slightly? Does anyone know the reasoning behind only covering the R2 release as a destination server? Is it purely because Microsoft would expect users to be running R2? From what I've read so far, the guide is silent with regards to the omission.