If you are using Hiro 5, then you are using GENESIS 1 base.
The only morphs that will show up as available in GENESIS 1 base are those made for that figure. You cannot install Genesis 2, Genesis 3 or Genesis 8 morphs and make them work on Genesis 1 base. So to work with any figure with the "5" name on it (ie: Genesis 1) keep in mind the 5 refers to the Morph (Michael 5), 6 is Genesis 2, (Michael 6), and 7 is Genesis 3 (Michael 7) and 8 is Genesis 8 (Michael 8). Hopefully that clears some things up.
The only way to use morphs made for other figures, is you must convert them, but most won't work since the topography of the figure (vertices and bones) are vastly different from generation to generation.
So, make sure when you get morphs for your Hiro 5, get things only for Genesis 1. Listings for GENESIS 1 are listed only as GENESIS with no numbering.
Good luck, hope my info helps you a bit.
AnjaBear