HTML comments causing an issue exporting CSS files with Grunt-usemin

问题

I'm using yeoman/grunt to for my build process and I'm running into an issue. I'm trying to build two .css files, one for IE8 and one for everything else. If I place the IE conditional on the outside of the build block, an error is thrown because of the comment within a comment. If I put the IE conditional on the inside it gets stripped out.

    <!--[if lte IE 8]>
    <!-- build:css({.tmp,app}) styles/main-old-ie.css -->
        <link rel="stylesheet" href="styles/main-old-ie.css">
    <!-- endbuild -->
    <![endif]-->

    <!--[if gt IE 8]><!-->
    <!-- build:css({.tmp,app}) styles/main.css -->
    <link rel="stylesheet" href="styles/main.css">
    <!-- endbuild -->
    <!--<![endif]-->

Is there another/better/easier way of doing this?

Thanks!