Disable Cassette.Net url() rewrite for a specific CSS rule

Question

I am using Cassette.NET to manage the static assets in my .Net application and have run into a small problem trying to use SVG filters in my CSS rules.

I have a CSS rule that applies a filter to text elements:

text {
    filter: url(#text-halo);
}

However, when the stylesheet is processed by Cassette it transforms the rule into

text {
    filter: url("/app/Content/css/#text-halo");
}

which does me no good at all. Is there a way to tell Cassette.NET to not apply its URL transforms to a particular file or do I just need reference this stylesheet outside of the Cassette.NET asset pipeline,