There is a new Effect available in SVN now. The "gradient" Effect allows you to draw vertical or horizontal gradients. You can use different colors and a percentage or pixel value for the position where the specific color should be.
Example:
<value offset="0%" color="#f00f" />
<value offset="20%" color="#0f0f" />
<value offset="60%" color="#00ff" />
<value offset="70%" color="#ff0f" />
<value offset="100%" color="#ffff" />
</onActive></pre></p>
Result: