You might contact one of the CNPS chapters or one of the native-plant botanic gardens (e.g. Rancho Santa Ana). I assume you have Dara Emery's "Seed Propagation of Native California Plants." He simply says "no treatment" for Fouquieria splendens seeds. Many decades ago, during my less enlightened years as a teenager, I dug up a small ocotillo and tried to grow it in San Diego. It survived until we moved three or four years later, but it didn't grow, either. I'd be tempted to try seeds, except that I'm not sure what I would do with the resulting plants. In my yard in Temecula, I'm trying to emphasize chaparral and CSS plants that could plausibly grow here. Whatever you find out, please keep us posted.