Here are some details for the modification of the RRD storage for the RAW edition.
Inside your site you find the folder ~/etc/pnp4nagios/check_commands. In this folder you can define templates for single commands how to handle performance data.
If PNP4Nagios finds a template file for your check command then it also looks for a file with name “template_name.rra.cfg” inside ~/etc/pnp4nagios/ and uses this definition to create the RRDs.
I thinks this procedure is really complicated for RAW edition. Inside enterprise edition you can define this RRA settings for every check inside the web GUI.
It is some years since i last changed these files manually 
All the code that handles this config files are inside “process_perfdata.pl” used by PNP4Nagios to write the performance data to RRD files.