You have to convert the file. The converted file will contain all your relationships, layouts, etc, so you are better off converting the file than you are importing the records. Importing the records will only pull the tables and their data into your file. All the rest of your design work will not exist in the file after import.
You could export all data in xml-format. .fp7 and fp12 ( and .fp5 ) can read this format easily and you can simply do 'matching field names'