www.gardeneradvice.co.uk - or just Google wisteria from seeds and it comes up, with other options, on that page - I think it said you can either sow immediately or keep till spring, nick the seed, soak overnight and then pot up in John Innes No. 1, keep somewhere warm for up to 60 days until germination occurs and I can't remember the rest.... If you manage to raise seedlings, they often take up to 10 years to produce flowers, though.

How nice to be able to grow your own, there is however a reason why they're expensive, time is money as they say.