Thanks Ryan, that is much easier! As Leonardo Da Vinchi was purported to have said: “Simplicity is the ultimate sophistication. " :)
I tested this out in the lab and it works just fine with enable_environment_macros set to 0 and no modifications to pagerduty_nagios.pl.
The guide is up to date: http://www.eventenrichment.org/integrate-nagios-pagerduty-engage-operations-nervous-system/