Bentley AutoPLANT V8i P & ID - Assembly file location path

I am currently investigating how to build standard designs for P & ID's and wish to alter the storage location (not on my C: drive) so other Bentley CAD users can access these assemblies.

I have read in the Bentley help files that the file path location can be altered in P & ID/Preferences...unfortunately this is not active in my drop down list...does this preference have to be switched on elsewhere etc.

Any help appreciated.