I don't know if anybody has tried this method for germinating dormant or frustrating seeds, especially Annona. However if they are similar to Mitrephora and other Annonaceae species then give this a go.
Clean & sterile the seed, wrap in moist chux cloth, place in sealed air tight clear bag and throw that on a heat mat. Some things just need heat from below. I was able to reduce the germination and break dormancy. I.e. some Annonaceae will take up to a year or more to germinate, the above method......4 - 5 weeks.