Seed transmitted disease?

[gill_s]

I have a severe disease problem this year on my tomatoes. At first I thought it was Tomato Spotted Wilt Virus but have now been told from a UK seed producer that it is almost certainly Bacterial Speck.(He refers to the 'Atlas of Tomato Diseases')
I have made extensive enquiries and not found any other incidence of it locally and have indeed not heard of any other in the UK. Does anyone know different? I have never had the problem before!
So now where has it come from? It can be soil borne or seed borne. I grow in 'grow bags' and containers using commercially produced potting compost mixes so this can hardly be the cause. I grow all my tomatoes from seed, not bringing in any 'unknown' soil or compost. It seems therefore that seed may be the culprit.
My main concern is how to go forward next year. Obviously I must be very rigorous about cleaning up my greenhouses and all tools and equipment and making sure all tomato and weed debris is removed from the outdoor growing areas also. I have quite a large store of seeds and would like to grow some varieties again next year.
How can I treat the seeds to rid them of this Pseudomonas Syringae? I have been given advice on a treatment for the seed coat. I have not been able to find out though whether this bacteria can be carried inside the seed.
Can anyone help with this information, please? I know that I could heat treat the seeds in a water bath at 122F for 20 minutes but this does reduce germination.
I am not sure which variety this started on. It spread very quickly so I would need to treat all my new 2010 seed varities.
In conclusion to this sad tale, it was to be my first year of seed saving! obviously that has had to be abandoned!
Please help with suggestions!
For information for anyone else with the problem two varieties which have shown good tolerance are Kumato and Sugary. All my other 65 varieties have succumbed, some worse than others!
Gill