Currently this isn't an option to map. However, you can use the u.addEvent method of accomplishing this.
If you are using the H25 or later version of the SC template you can do this:
You would use this in a Set Data Values Extension like so:
Set: sc_events To: JS Code --> u.addEvent('event5',b.material_Count)
If you are using the H24 version of the SC Template you will need to use:
And setup your Set Data Values Extension like:
Set: sc_events To: JS Code --> u.addEvent('event5='+b.material_Count)
See the "Setting s.events in Extensions" section of this post for more information about using the u.addEvent Method:
The u.addEvent function is not supported in versions prior to H24. If you are using an older version of the SiteCatalyst template I would recommend reaching out to your Account Manager to get some help setting this up.