To answer your questions; I do not know if you can convert them. They do not provide a utility.
So if you can work out how to convent them a lot of people will want to know how to do it.
CENTUM VP graphics are not HTML5 natively and require conversion to run in a browser.
I ran into the same issue and ended up building a converter ourselves — parses CENTUM VP files into HTML5, pulls live data from IP.21.
Works with Honeywell EPKS and Foxboro too.