How can I build a DNG (digital negative, or RAW) image file with MATLAB?

This link explains how to read in a DNG file's CFA using MATLAB's TIFF library. I would like to do this in reverse, I have a CFA (which is not in any standard RAW file format), and I would like to create a DNG file from this.

I have tried to build up a DNG file, but the images are never readable if I set the image's "Photometric" tag to CFA.

Does anyone know how to do this?