I had a similarly cracked on my previous '95 900ss. Get on to Ducati UK Customer Services <Info@ducatiuk.com>. They will ask you to take the bike to a Ducati dealer who will then confirm that the frame is indeed cracked. All going well they will offer you a replacement frame but how long it takes will depend on availablilty from Italy. Last year, Mike Vaughn had to wait more than 6 months. Their offer wil not include labour but they will probably allow you to do the work yourself. In my case the dealer wanted the old frame before they would hand over the new one. I stripped it down in a day, did the exchange with the dealer the following day and rebuilt it over the next 2 days with an excellent opportunity to get everything nice and sparkly clean at the same time.
Here is the original thread
http://ducatisportingclub.com/xmb/vi...=6410#pid51974