at the risk of giving away some sort of advantage.... these seeds need to be "coaxed".
take a little razor and scratch the seed where the root emerges. ive been doing this for a while now, and its remarkable how well it works. ive done this with many annums that seem to have a tough time poping the root out. if i had to guess id say this will work for pretty much any seed that has swollen but is not able to pop.
i usually dont bother doing this, but for the sake of experimintation.
basically soak them till they swell... then scratch the seed open. mine poped 12 hours later.
if i had to guess the seeds are basically mechanically unable to let the root out? pretty much sealed shut. it also may be that the scratch or puncturing is actually letting more moisture into the seed allowing it to germ faster? id guess its the former however, given the seeds already swollen.