Accessing active submaterial in a slot - problem.

Hi,

I created a script that proessed the material in active material slot which I took from ActiveMeditSlot system variable. It worked well untill I tried to process a material from a multi/submaterial.
The problem is that ActiveMeditSlot returns the array of all materials instead of one active material from multymaterial currenlty opened in the slot.
Are there any ways to access current material if it is a pert of multimaterial?

Thanks.