Just dealt with this...had them all sink after 24 hour soak. Planted them...only 1 popped out of 4. Dug the others up, none had even cracked yet. Put them in a paper towel-moist, Baggie-ziploc, outside-heat/light, checked today and two have tiny tap roots, 1 had an inch~ and was trying to open its shell In the papertowel lol.
Morale of the story:soak, moist enviroment, and enviroment temps of 76F+ because your medium will always be cooler than that if wet.