I use backyardeos with a canon 30d and needed the shoestring cable in addition to the USB. Guy, who distributes will generally ask you what camera you are using when you order. Check with home first.
Please note though that I also have a 20d and this does not work well with windows 7. There are no canon drivers for this combination...there are ways to download just images to a pc with win7 from 20d but it will not work with BYE.
I have not tried DSLR Shutter, but I assume that if there are no canon 20d drivers for win 7 then I question whether this would work properly either. Same goes for canons own utility.
With the 20d I basically used to frame and focus without any gadgets and it works very well, but you do miss the capture management stuff.
Bojan, just reading your post, you mentioned you had a 450 working with win7, do you also have a 20d? If so, and you have it fully working with capture management software can you post how you did it cos I am stumped.
