As of 1.0 build 31537 you can use the following URL to open documents in Vizit Pro™:

http://{server}:{port}/_layouts/Vizit/Viewer/Default.aspx?{options} 

Options need to be formatted as URL query string and can include the following:

1. File reference by SharePoint list URL(L), internal ID (D) and, optionally, page 0-based page index (P). Example:

   Default.aspx?l=/Docs/Documents&d=55&p=1

2. File’s absolute URL (U). You need to specify full URL and can use optionally anchor to reference the page. For example, if you would like to open the page 5 of the /Docs/Documents/myfile.tif, you can use the following URL (page index is 0-based):

   http://{server}/Docs/Documents/myfile.tif#4

   and the following parameters:

   Default.aspx?u=http://{server}/Docs/Documents/myfile%234

   Please note that URL must be properly escaped (i.e. # needs to be replaced with %23, etc)
3. Configuration script URL (CFG). As of build 31537, Vizit Pro™ appearance can be configured via configuration scripts. You can optionally specify which configuration you want to use by providing the JavaScript file URL in CFG parameter, for example:

   Default.aspx?cfg=/_layouts/MyCompany/vizit_read_only_profile.js

You can open multiple pages at once by referencing several files:

Default.aspx?u={url-1}&u={url-2}&l={list-1}&d={id-1}&l={list-2}&d={id-2}