ACTIVE/ACTIVE SQL Server 2000 Cluster

This was my plan.

Physical box - box1,box2
virtual box - virtual1

i have a active/passive cluster virtual1 (primary node box1, secondary box2)

I am creating another virtual box on box2 as primary node by name virtual2)

whenever my installation setup runs my default server name is greyed out. it always requires a instance name.

Is that the way it should work?

i can only use instance for active/active failover?

please advice