How to "repeat-x" a sprite, generated by Compass

I have a gradient directory in my assets/images in a Rails 3.1 application. Here's the code I use to create a sprite from those images using Compass:

 $gradient-repeat: repeat-x;
 @import "compass";
 @import "gradient/*.png";
 body > header > nav {
   clear: both;
   @include gradient-sprite(red-menu);
 }

开发者_StackOverflowMy problem is that even though I explicitly tell Compass that I want my background to be repeated horizontally, it still produces the following CSS:

 body > header > nav {
   clear: both;
   background-position: 0 -207px;
   height: 34px;
 }
 .gradient-sprite, body > header > nav {
   background: url(/assets/gradient-sbe06665f77.png) no-repeat;
 }

and so my gradient does not get repeated horizontally.

I'm using the 3.1 branch of the Compass gem in my Gemfile.

Now, I could simply add a background-repeat: repeat-x; to my code and override what Compass has generated for me, but that I feel is not the Rails way of doing things.

Any help would be greatly appreciated.