Why can't I copy certain PSP games from my PS3 to my Vita?

I purchased and downloaded Motorstorm Arctic Edge to my PS3.  I plugged my Vita into my PS3 and ran the content manager, but my Vita doesn't seem to be able to recognize the game at all.  it doesn't appear in the content manager.  Does anybody know why certain PSP games can't even be copied from the PS3 to the Vita?  I live in North America.  I understand that people in Europe are able to get this game to work on their Vita's, but people in NA can't.  Does anybody know why that is?  I searched the web regarding this issue and I haven't really been able to find any info on it.

It is an allocation in memory that is different so as most of the new systems they changed the hardware and the way that they read the software so you can't use that games sadly. So far there are better games for the PSP than for the Vita

I thought all PSP games were BC on Vita? That's just ridiculous.

So far there are better games for the PSP than for the VitaPipeBigboss