To get a gradient background in IE browsers, use the following CSS style code in a custom header or code object:
<style type="text/css">
body { filter:progid:DXImageTransform.Microsoft.Gradient
(startColorstr='#FFFFFF', endColorstr='#7FFFD4',
gradientType='0'); }
</style>

Change the startColorstr and endColorstr values to the hex color values you desire. Change the gradientType value to '1' for a left-right gradient.
The gradient effect is not limited to just the body tag. It can be applied to a text object.