Hi I heard a lot about the new reverb Rematrix Solo but I cant find it exept in the ProChannel inserts. I rememper seeing a video demonstration of it in full VST form...

The version included with Sonar is only a ProChannel insert.  The full VST version requires a separate purchase and it doesn't run as a ProChannel insert.  They have a demo version if you want to give it a try.  I've been using it a lot lately, the factory library that comes with the full version is very nice.