Maybe what I'm going to say makes little sense, so please forgive my ignorance...
I think the normal case might be someone having both a PKG and a RAP file (e.g. some game). My case is wanting to add custom-made songs to my legitimate copy of Rock Band 3 on BD disc. For that, I am told I need only two things:
a) FTP my songs files to the correct folder (that's why I need HEN in the first place, so that I can use MultiMAN or something similar)
b) install a specific RAP file, which on CFW is done using PSN Patch
If I understand correctly, the RAP file makes Rock Band 3 believe my custom songs are part of an official "pack", even if I do not have any packs (and I don't want to get the PKG file of a pack illegitimately).
So now I am confused about how do I install such RAP file without having any PKG to go with it...
What happens otherwise, if HEN is installed before dumping?