Wow thanks guys - I've just ordered a JB3 so now, if I pull this off, I have the luxury of 3 rigs! Now that is just plain greedy.
But I am still a little baffled (or just plain thick) - the roller seems to be jammed fast, and I am worried about breaking something. I presume it has to be pushed forward into the niche (in which there is also a little spring), situated diagonally upwards and right of it(on the picture). If this is the spot, I can't see where and what I should glue.