They are then 'banked' for 7 years validity from the date of expiry of your most recent IR (this can be an ICAO IR, and in your case your B747/IR rating would suffice) for the future upgrade to the full JAR ATPL.
Got a reference for that?
Also be aware this
no longer exists under the new EASA regulations - you must keep the EASA IR current which gives you 7 years every time you retake the IR.