i didn't clearly understand how works the plugin, could you please explain some things?

Our website provide medical consultations (from the side of VirtueMart component the consultation is the item) and we need a possibility or method to upload files by customer on the checkout step.

On our website it looks like that: http://joxi.net/Drlan40IjZJJmP
I understand, that it requires additional development, but it’s important to attach files on the checkout steps, not on the detailed product page. We don't need this buttins here: http://joxi.net/KAxeO4LTj5Ylr8 , but only on checkout step

So my questions:

1. Does your plugin works on the multiple checkout steps? (VM settings: One Page Checkout enabled - NO; Show checkout steps - YES;)
2. As far as i understood from your video-tutorial, the file upload available only after user authorisation: http://joxi.net/8AnXveqikJnemO
I don't see this field on your demo web-site: http://joxi.net/5mdk8JqtLz6Lr1 Where is it? Is it available only after login?
3. I check your other demo-link and it looks great: http://joxi.net/krDpNXMCXj3Rrp
But i don't see the file upload on the checkout step again: http://joxi.net/v29QZ6piwyLz2G
4. Is it possible to remove

So, is it possible to add this field on the checkout step? I mean here: http://joxi.net/5mdk8JqtLz6Lr1