Exporting Intrinsic Matrix as .xml file, Camera Calibration

How do you export the cameraParams, specifically the intrinsic matrix in an .xml format? There is a tool called rectifyExtreme which asked from a .xml file of camera intrinsic generated from the matlab camera calibration toolbox or the caltech toolbox in matlab, however neither offers an option for exporting as .xml, and the rectify Extreme software does not specify how to do it.