Create project via API - no extended fields respond

I’d trying to create a project via API, and want to set more than just the client_id and name. At a minimum I think I should be able to set the task_rate and budgeted_hours. Nothing I’m doing is working though to get those other fields through, the first two, if alone, work fine.

Is this simply not available, or do I need to do something differently? Thanks!

me@me ~ % curl -X 'POST' \
  '' \
  -H 'accept: application/json' \
  -d 'client_id=IelazUdJ2&name=tester testerson&budgeted_hours&10&task_rate=50.00' \
  -H 'X-Api-Secret: password' \
  -H 'X-Api-Token: _long_ol_token_here_' \
  -H 'X-Requested-With: XMLHttpRequest';

This was a test for Zapier’s webhook… for anyone reading this, when I structured the request in Zapier it worked just fine once I got all my other settings right.