Get all categories from search result

Hi,

We are changing our customers search from SiteSeeker (implemented before I started) to Episerver Find, but we want the search page to look the same.
The current search page have a list of all the categories from the current search result, to be able to filter if the user wants to.
In SiteSeeker we seem to get the categories by getting them from result.Facets.
With the same pages and the same search word, in Episerver Find, the result.Facets is null.
Is there some way to get a list of all the categories from the current search result (not all the categories on the site) in Episerver Find?

Edit: We are using UnifiedSearch.


Best Regards
Niklas Grushult