Don't know specifically for the punto but I suspect it's going to be the same as for the cinquicento which means that you can't fit the bottom belt because of the tdc (timing) sensor. This needs to be removed and the only way to do this on the cinquicento is to take off the wheel and the inner plastic wheel lining. This gives you decent access to the alternator.I wish I'd bought the manual before I invested in an extra-long socket spanner.
John Lawton (complete amateur), January 2007