There are two reasons why this button may not appear for you or your end users:
Uploading a new Login Form is easy, though it does offer some restrictions depending on the type of product you subscribe to.
Which login page gets customized?
By default, all customers get one complimentary customized secured PDF and/or Web Viewer login page (secured web link). These login pages can be customized by incorporating your company logo, as well as any extra verbiage you wish to be included (instructions, guidelines, etc). You basically need to send us your company logo, along with any instructions you wish for us to incorporate on your login page.
What style of image/logo do I need to provide?
We will need a copy of your company logo in a vector-style format. Vector images usually have file extensions like .png .pdf .eps .ai .svg .bmp .jpeg
How do I upload it to my account?
Standard Edition accounts cannot upload it in their account on their own. This is a feature only available for our Pro and Enterprise customers - we would have to upload it for you ourselves :)
Pro and Enterprise Hosted can follow these steps for instructions on how they can upload their login page to their account after our staff at Vitrium has modified the login page(s) for you. Understand, however, that both types of customers can only upload the secured PDF login page and not the secured web link (Web Viewer) login page - we can do this from the back end for you: