Again, just add me on skype. From this comment it sounds like your just rendering something recursively but nothing else, which would make sense why its just entirely white and nothing else?
My setup uses two blueprints, a portal and an exit node. The exit node is where it teleports the player and also includes a scene capture pointing away from the portal. The portal is linked to the exit node, grabs the scene capture and applies it to the portals material. Nothing points directly at the portal itself.