I use lots of poser content in C7 and the highlight, bump, and shininess need to be adjusted almost every time.
Usually I turn the highlight to a percentage, rather than a color. The bump usually needs to be reduced.
I could give a few tips here, but they are all covered beautifully (and better than I can do) in the fruits tutorial over at carraralounge.com  In that tutorial, they build new shaders for each fruit, during which they explain just what the highlight color is doing. Highly recommended.