Add custom property to BOM Export

I'm trying to figure out how this works, and I'm stumped.  I want to add a custom property "material" to the BOM output, but can't figure out where in the code I'd add it.

I'm playing around with the macros.zip file in https://forum.solidworks.com/thread/27702

Is anyone familiar with how this macro is written and what would need to be changed?

SolidworksApi macros