How do I register a Go To Webinar attendee to a specific session using their API V2?

Question

OK so...through a custom form, I am successfully registering attendees to Go To Webinar but am blocked if there are multiple sessions of the same webinar. Currently, I am returning scheduled sessions to populate our dropdown menu (response shown below) but am challenged with passing back sessionKey with the registration payload. Has anyone successfully done this? Help! I've also put in an inquiry with GTW so will let folks know what I hear if others are struggling with this also. Thanks!

[{
    webinarKey: xxxxxxxxxxxxxxxxx,
    registrantsAttended: 0,
    webinarID: "xxxxxxx",
    sessionKey: 666666,
    startTime: "2020-05-06T19:27:54Z",
    endTime: "2020-05-06T20:01:13Z"
  },
  {
    webinarKey: xxxxxxxxxxxxxxxxx,
    registrantsAttended: 0,
    webinarID: "xxxxxxx",
    sessionKey: 777777,
    startTime: "2020-05-07T19:26:08Z",
    endTime: "2020-05-07T19:26:43Z"
  }]

Answer 1

1. Populate a list for the webpage visitor using Scheduled webinars
2. An interested individual selects a webinar from the list and you submit their details using Create registrant

For step 2 you should also know the following:

To use the second version of the api you must pass the header value

'Accept: application/vnd.citrix.g2wapi-v1.1+json'

instead of 'Accept: application/json'.

Leaving this header out results in the first version of the API call.