To be able to use the Find, New and My Service Manager pages for different Sage 300 databases you have to modify and duplicate CRM menu entries.

In Sage CRM use Administration > Advanced Customization > System Menus to update the URLs for the Service Manager Entries for Find, New and My Service Manager.

Add this:

 ?database= SAGE300 _DB_ID

at the end of the URL and replace SAGE300_DB_ID with your Sage 300 database ID.