How would I create a Reservation, plus any extensible attributes? [ Edited ]

[#1]

Right now I can create a reservation, but it doesn't help me much as I need to manually go in and set the extensible attributes. I can see how I can add extensible attributes to a network, but not how to do it for reservations in a network. 

[#2]

See below, except use a reservation object:

https://community.infoblox.com/t5/api-integration-devops-netops/api-wapi-network-creation-with-exten...