SOLVED!
Win Vista and 7 do have problems with sbp2-protocol over firewire. A solution is provided by using the drivers from Unibrain /(https://www.unibrain.com).
same problem here with du-1 with dsr-500 on windows. av/c-protocol is no problem, sbp2 doesn’t work. i’m getting a sony device with a call sign in my device manager, but no drive to select.