If I could only know how I could access the output directory from within a script that would be a good start.
I feel like the scripting guide is for writing scripts to process the RH source files, rather than the output. I think the post generation script is supposed to be something like a .bat file using perl or node.js or something. So I think you would need to look at standard scripting languages for output manipulation.
This is also assuming you want to run the scripts before publishing the output, rather than scripts that will manipulate the content for the user at runtime.
However, I only know enough about scripting to get myself in trouble.
I suggest you try support, using the email address on this page (the email will get to Robohelp specialists rather than general Adobe help desk staff).