Generally, VFT seeds do not require stratification if sowed fresh. I do not have experience with VFT seeds stored for long period of time. I have read that stored VFT seeds are not as viable as fresh VFT seeds. Are your seeds fresh?
Hmmm!! would it be another way of saying storing seeds??. Nobody as far as i know has shown whether stratification is in fact necessary for successful germination.
I would say that when seeds are produced (from plants of cold-temperate climates), usually there is a 3-4 month period of inactivity before the growing season starts again. So keeping the seeds in a fridge, would be like mimicking mother nature and thus, keeping them safe until that time comes again!!.
The proof is that VFT may go dormant in winter, but the seeds can be germinated at any time. Maybe keeping seeds viable is the function of stratification.