Putting it simply, you don't. About the best you can do is to let the seed fall around the original plant and hope for the best.

That's more or less what I was going to say, Owdboggy, but I was hoping that someone would come up with a method.

Well if you have access to various Laboratory equipment it can be done.

agar plates with the correct fungal co-host are possible. Back at uni in the late 70's we had to try this method, cant remember why or the recipe/fungus. I seem to remember about 30% success rate. The plants were then planted out in the wilds some where.