Look into having a generic CAT welded in instead of bending over and buying the head pipe CAT assembly. Been there done that man times when I had a shop.
The techs at Government Smog centers are not the brightest and if they were, they would find a job some place else that pays more like the TSA or an oil change center like Jiffy Lube.
Since your CRD is not CARB approved, welding on a Performance Diesel CAT that meets or exceeds the OEM specs will get you to slide by and get your CRD approved. If you can't get a California exhaust shop to weld one on, you may need to border hop to Oregon, Nevada, or Arizona. If you want to border hop to where they speak Spanish, good luck.
Just make sure the flange is at least 2 1/2" ID for what ever you have welded on.
http://www.amazon.com/Magnaflow-94115-U ... &carId=001
If you have to, tell the Smog Tech you punched a hole in the original when rock climbing and had a new CAT welded in to save the planet.