I missed whatever webinar that is... but the way it actually works is:
vCD 1.5 -> Blocking Task -> AMQP Server
Then, vCO uses AMQP Plug-in to subscribe to AMQP server and workflows are used to extract data from the AMQP messages.
Finally, vCO uses the vCD 1.5 plug-in to resume/abort the blocking task in vCD.
You are correct, there is not a DIRECT method of vCD starting a vCO workflow, you must use AMQP to accomplish this 