vApp cannot be created by the Admin OnApp user
OnApp 5.2.x (and later) with vCloud Director integration
At this time, there is no option to create a vApp when you are logged in as an OnApp admin user. If you log into an organization user's account, you will be able to deploy vApps on behalf of users there.
This is not possible as it would be created in the same way that a vCloud System Administrator would create a vApp, causing 'system' to become an owner. OnApp does not manage any resources owned by the system users.