You can't use it fully, but you can access its menu. I have a button combo to skip the ID check for testing stuff (This is how I found the Pokebank thing). Target a title that JKSV can run under and hold L + R while the debug info and colors flash on the top. You should now have the CIA version's menu. Try using the cartridge menu to get into MHS's extra data. It should work since it saves to extdata.
If not, someone can get its ID and I can make a quick program to grab its data with that file lib I wrote to speed stuff up.