How can I generate CSS image sprites using YAML 4.x

How can I generate CSS image sprites using YAML 4.x

The version 4.x of YAML includes lot of features but the most important
for me is integration with SASS and Compass. For enabling SASS support in
YAML 4.x you have to install Node.js and Grunt (among other things), but
after that you have a really nice set of tools for automatize SASS
compilation, etc.
I was using YAML 3.x and Compass as a stand alone tool for generating CSS
image sprites, now I'm trying to realize if it's possible to generate CSS
sprites images using the integrated tools included in YAML 4.x.
I create a test.sass file, and include the line
$icon-sprite-dimensions: true;
@import "../icon/*.png";
@include all-icon-sprites;
but when I compile using grunt build, the following error is raised:
Running "compass:css" (compass) task
TypeError on line ["27"] of
/var/lib/gems/1.9.1/gems/compass-0.12.2/lib/compass/sass_extensions/sprites/image_methods.rb:
can't convert Array into String
Run with --trace to see the full backtrace
Any idea how to generate sprites using YAML 4.x??
Thanks in advance.