Unattended/built issue for vsphere image based provisioning without ssh

I was able to get image based provisioning without SSH working for a
vsphere compute resource:

But I'm having issues automating the build completion. The VMware
is very limited in what it can do for Linux so I've been working on a
firstboot process to complete the provisioning and hopefully call
unattended/built?hostname=<my hostname> from the client, but that does not
appear to work without authentication. It looks like token is what I should
be using, but it's impossible to get a token to the client using vmware
user data.

Any idea on how to best automate the build completion?