Is it an OEM version of SBS? If yes, then you can't move it to any other hardware. It will only work on the Original PC it was activated on.
If no, after the restore, boot the server using Paragon's Adaptive Restore utility. It'll remove drivers and HAL (and you can also add the new drivers for the new hardware via USB stick, so the y will automatically install), then reboot the new server to the new OS. It should find and install new hardware and after that run OK (you might have to change settings, like which NIC uses which IP).
http://www.paragon-software.com/downloads/business/