cristian I've moved this as a feature request as RN normally do not generate not meshable objects previews. This is quite problematic as lines/polylines/curves can be pretty heavy for display and basically, what you're asking for is to show the original content of the block so there will be very little gain in performance in comparison to regular objects in the viewport.
It's not impossible but not efficient. I think this could fit in the Original appearance somehow. For now, I will explore possibilities before adding this to a pile.
That being said, concluding from the screenshot I highly encourage you to use the Lands Design plugin for landscape design as this is what it aims for it has a bunch of great things for landscape designers, plus I'm already in contact with Asuni and we want to create a unique synergy between LD and RN to enrich landscape designers workflows.