You can use the command-line tool, ImpExpCmdTool, to import an object store.
NOTE The use of Enterprise Manager or its related command-line tool to create an export manifest, or to export or import objects, is deprecated and it is recommended that you use FileNet Deployment Manager instead for these operations. For more information, see Exporting and importing.
The command-line tool imports all the data in the XML files into the specified object store.