CambridgeSoft have released an update for the Mac version of ChemBioDraw, this update in part addresses the issue of roundtrip editing.
This footnote will be of particular importance to users who have their own templates or scripts:-
"Please note, the location of the ChemDraw Items folder has changed in this version. The new location is located here:
Macintosh HD/Library/Application Support/CambridgeSoft/CS ChemOffice 2010/ChemDraw Items"
If you want to have custom templates or scripts available to all users then you need to put them in this folder. It is not clear if they will be overwritten with future updates.
Alternatively you can create a folder at:-
Username/Library/Application Support/CambridgeSoft/CS ChemOffice 2010/ChemDraw Items
If you put templates or scripts in this folder they will be picked up by ChemBioDraw presumably not overwritten with updates but will only be available for one user.