http://screencast.com/t/n2narJ3j
The image above shows there are no pre-defined behaviors for the Create PO Policy and no option to create new behaviors. Compare that to the next linked image for Purchase Invoice Policy which has both.
http://screencast.com/t/8ndk5W6fkRsK
This is a brand new installation of GP Web Services on my local machine. This is GP 2016 - why isn't there an option for that in the drop-down yet?
What do I not know about these Policies and Purchase Orders?