From Trammell Hudson's Projects
First you need to select a color space for your document. This will set the ICC profile field in the SVG's header (Is this OK that it refers to an OSX specific file?):
<color-profile name="Generic-CMYK-Profile" xlink:href="/System/Library/ColorSync/Profiles/Generic CMYK Profile.icc" id="color-profile3295" />
Then you can select the "CMS" color picker to associate a fill with a specific color profile. This will set the fill or stroke on an object with both a fall-back RGB value as well as the ICC profile color.
style="fill:#a84272 icc-color(Generic-CMYK-Profile, 0, 0.79411763, 0, 0.25980392);fill-opacity:1"