Reflection Capture Problem

the problem is… that even using a planar reflection… the mirror itself is not just flat and planar. The mirror has additional forms, and shapes. like little bumps inside every section.
I also tried the SceneCapture. But the problem that you’ll run into … is the fact. that the SceneCapture is just a projection… and therefore… in runtime… the reflection is not dynamic.
Uff… I am assuming… a space with huge mirror walls… it’s just not doable at all in runtime… or am I wrong here?