It could be difficult to mimic the response of the website in VWR because it is using the Internet Explorer as web browser emulation and it has difficulty capturing the necessary actions.
I tried it in our premium software, the Content Grabber and it works well using advanced event configuration. Content Grabber uses Chromium browser instead of IE and much easier to capture and mimic the events.
Attached is the agent for Content Grabber. You can download the trial here.