Portico Products will supply a strap to replace the spring metal straps originally fitted by Rollexa. However, these straps are thicker than the originals so the door winds up a few cms higher - and in my case stopped above the vertical guide rails.
So you have to change the limit switch position. Do this by winding the door fully down. On the side of the motor are two press buttons with arrows showing direction of rotation of the roller drum. Select the press button adjacent to the arrow in the direction of the roller winding up. Depress this push button and wind the door up to the height you want it, stopping it with the remote control. Release the push button. This should have set the limit at that position. You can also adjust the down position with the other push button. May all need a bit of trial and error.
Tony
April 2010