Delete other APNs
Success! and Thanks! My Moto Atrix 4G came with other APNs configured for AT&T and Cingular. I deleted them, leaving only the ConsumerCellular APN that I created according to Garst's specs. Now everything works fine. Previously with the other APNs present, even though I had selected the ConsumerCellular APN radio button, the data would not work.