openconnect derailed by Pulse pre sign-in notification?

[James Ralston]

Does anyone have any advice or tips for getting openconnect to
navigate through a pre sign-in notification?

We are legally required to use a pre sign-in notification for our
Pulse VPN service:

    https://corliss.sei.cmu.edu/

Unfortunately, openconnect doesn't seem to understand how to navigate
through the pre sign-in notification.  Attempting to connect to the
Pulse VPN service yields this error message:

    Failed to find or parse web form in login page

Looking at the generated log, I see:

    Ignoring unknown form submit item 'sn-preauth-decline'

So, it seems pretty clear that openconnect doesn't understand the
form.

Is there any way we could tweak the form, so that openconnect
understands to select the sn-preauth-proceed input?  Or better yet,
have present the form to the user, and have the user manually select
the "Proceed" option?