Maybe take some and soak them overnight in water..give them a nick with a file or something. And it always helps to use a heating pad under them. Hydroponics stores carry them more often then nurseries I just learned. $25.

Ok, I put a few directly in the paper towel and some I let soak over night. Should I nick the ones that are already in the paper towels? How long do cherimoya seeds last? Is there any way to tell if they are viable before waiting for them to sprout?

I planted about 25 seeds and only got 4 to germinate, and that was AFTER I gave up on them. I ended up just sticking some other seed in the same growing pot and waiting for those to grow. I was about to dump the whole thing out when I noticed four little sprouts. It must have taken months. I had them in a damp paper towel for about 3 weeks prior to planting them. This was my first time though so maybe there was a better way to go about it.