It is possible to integrate PrintSYS Store with Post Affiliate Pro, but you have to contact them directly to ask them to insert the tracking codes for you.
Click tracking code
First, you have to ask PrintSYS Store support to integrate the click tracking code into global footer, so it appears in every page of your store. The click tracking code can be found in PAP4 merchant panel Tools> Integration> Click tracking
In case of sale tracking, here is a sample code for your "thank you page".
Ask them to replace hardcoded values with their dynamic variables.