Section G1.2 of LASORS specifies that the 500 multi crew hours must be on JAR25 aircraft and I would suggest that a sim is not an aircraft. But you could always read JAR25 and see what its definitions actually are. "G1.2 notes" goes on to discuss that 100 hours max sim time can be included towards the 1500 hours in total. Makes no mention of multi crew time so I would say no.
When in doubt give them a call but preferably get it in writing so an email/registered letter may be best.