From my plant book, The Manual Of Woody Landscape Plants, by Michael A. Dirr...."seeds exhibit a slight dormancy which can be overcome by stratification for 30 days at 41 deg(F) or by soaking in water for 48 hours".
Most woody plant seeds will go into a dormancy when dry and some even when fresh. This dormancy will need to be broken for the seeds to germinate. The way I have heard of this being done with osage is to place the hedge apples in a bucket of water and let them over winter. In the spring pour the slurry of the pulp and seeds in a trench and cover it. After a short time they will germinate. In this situation I would allow the seedlings to grow until next spring then transplant them where you want them.
If you can clean the seeds from the dried fruit, I would place them in a zip lock bag with some damp(not wet) sand, place them in the refrigerator for a month then take them out and plant them. The month in the cool frig should break the dormancy and allow them to germinate.
