I had same problem with my C220. Then I wrote to Konica minolta support with the output of cupstestppd.
They sent me a ppd which solves the problem.
And the color/grayscale settings are there and working as well :-)
Pascal
---------- Post added 09-07-12 at 03:41 PM ----------
You can find the ppd here:
http://dhermilly.dk/pascal/KOC360UX.ppd