The easiest way of accomplishing this would be to use a template which deploys those network settings to the device. In the API, there is no "provisioning" of a device, only "deployment" of a template.
To my frustration, I haven't ever been able to include more than one target, so you may have to issue a POST for each device you're "provisioning". Even worse, I have been unsuccessful in getting the deployment to take at all. Looks like the softwareType, deviceType, and softwareVersion are more sensitive than in the GUI.
Your post was made awhile ago, if you've successfully gotten this operation working, we could all use the secret sauce.