By roof rack, I assume you're talking about load bars? If that's the case, you might be able to find a universal-fit bike carrier that would work with your Saris load bars. I know that Yakima makes several universal styles that are intended to fit a variety of different factory crossbars for different cars, and Thule probably does as well.

EDIT to add link to an example:
http://www.yakima.com/shop/bike/top/forklift