Are you sure you the punch is centered on the pin???? What type of punch are you using? Drift or a pointed type? You may have enlarged the end of the pin you have been banging on. Punching them out is the easy method, what follows is only slightly more involved and possibly more rewarding than opening your wallet to get the same product.
Don't let this thing get you down! Let's sneak up on it from the hind side! [>:]. If your pins are like the ones on my flywheels, the heads have bull's eye rings on it. Take a center punch and indent center, insert pilot 1/8" bit in press, secure flywheel, do both all the way , insert 13/64" bit and drill those hummers on thru. You'll loose the head and free the starter lug very quickly finish on thru the pilot hole will help(I like slow speed and some coolant to save the bits a little longer) DONE. (if you right on center you may see the spine marks in the bore.
Same procedure would work from back it you are sure of center. Really no biggy if your off abit the amount of alum wt lost will be minimal.
Post back when your finished.
Gone but lurking.......