Rails asset tag helpers outputting invalid xhtml

I am using Rails 2.1 and HAML for some, but not all, of my templates.
All of the self-closing asset tags (<link>, <img>) output by the rails
asset tag helper methods are not being closed at all, thus rendering my
pages as invalid XHTML. Has anyone else dealt with a similar problem? I
am completely out of ideas, so if you have any suggestions, by all
means, fire away. Thanks.