I feed ALL sorts of veggies raw. It is great as a filler (if you want your dog to eat less chow). I feed my older dog lots of veggies because I don't want him to gain too much weight because he is a dachshund and they have back problems if they get to heavy, plus, he loves them.
http://www.petsdoc.com/html/askthevet/askthevetquestions/fruitsandvegetables.html
The BARF diet (which I do not feed) suggest feeding veggies and also says that dogs have been eating veggies (particularly leafy greens) for their whole evolution.
http://www.barfworld.com/html/barf_diet/barfdiet_specific.shtml
The next site I am going to post talks about how some dogs do better than others with veggies but the same could be said for all sorts of things (as the article points out).
http://www.petsage.com/art_nut.htm
Mordy, who many consider to be the one to ask when talking about pet nutrition on this site, advises feeding veggies. I'm sure she wouldn't mind a pm, or maybe she will see this and respond.
Anyway, my whole point is, it is perfectly fine to feed veggies and fruits. The amount you feed will depend on the size of your dog.
I did find sites that say not to feed veggies raw. However, most that I found were people talking about what they do rather then vets or experts talking about the subject.
Probably you should do your own research and decide who is more trustworthy.