Hope we're talking about the same camera ... this one?
http://www.flickr.com/photos/lordcroker ... /lightbox/ The stud is a) hollw and b) cut twice at an angle of 90° ... so, with a thin and sharp knife you may slide into those cuts and caaaaaaarefully bend the segments outwards, just a teeny bit.
What have you got to lose?
A non working lens cap holder stut vs. a broken off lens cap holder stud.
Otherwise you'd have to reduce the diameter of the hole in the lens cap ... I guess your cap is brass, so you may solder some steel or brass washer to it with the proper diameter hole (naaaaah!).