Hi Del,
The above answer is quite correct and will work very well. However, there is another way. If you upgrade to the very latest release of sail on your existing box then there is a feature in globals which allows you to save/restore your SAIL "personality" to/from a USB stick.
Build your new system. Install SAIL and asterisk. Shove your USB stick in a USB shaped hole and upload the personality to the new box.
Job done.
Kind Regards
Selintra