Custom refinement webpart - obtain RefinementManager object

Hello,

I am struggling with extending the OOTB refinement webpart. What I want to do is adjusting the XML holding all refinements and values to display the translations of some terms.

I follow the 2010 example found on a blog (Timmy Gilissen). I understand how the person does it in 2010 but in 2013 I am unable to retrieve the RefinementManager object and so I can not get the XML (RefinementManager.GetRefinementXml()).

I already tried inheriting from Microsoft.Office.Server.Search.WebControls.RefinementWebPart and Microsoft.Office.Server.Search.WebControls.RefinementScriptWebPart.

Can anyone please point me out the right direction please?

Thanks a lot!