You have to use the EVF with the 18-55 lens on the Xpro1. OVF doesnt work.....
That's not what DPReview says:
"The 18-55mm can of course also be used on the X-Pro1, and when shooting with the optical viewfinder, the frameline will zoom to match the current focal length. The camera will set the viewfinder to its lower magnification by default, to accommodate the wideangle end; you can manually switch over to 0.37x magnification to get a better view when shooting at 35mm or longer. The size of the lens barrel does however mean that it will block a substantial fraction of the viewfinder at wideangle settings."
(see the X-E1 preview)