I am having difficulty driving the roll pin into the trigger guard assembly.  I can't keep everything steady and get a good strike on the roll pin.  I have already caused a small scratch around the hole (i am using tape).  Suggestions would be greatly appreciated.

use a block of wood to support the opposite ear, Have someone hold the lower while you hit the pin. I personally hold the lower on the edge of my wood table while holding the pin at the same time and whack the pin with a hammer in my other hand. Chamfer the pin a little to help get it started. Pretty easy stuff really. How you missed bad enough to hit the receiver and scratch it is beyond me. Maybe try opening your eyes lol j/k

I eventually got it.  I was using a block of wood as you mentioned.  I believe the problem is the punch I got from Brownells is maybe a little too long for my liking.  If the shaft was a little shorter, I think it would have been easier to hold the roll pin and punch between the thumb and fingers while freeing the other hand up to hammer with.  I didn't really scratch very bad but I still feel like a dumbass.  

This may sound stupid but trust me.  Check the diameter of the roll pin.  IIRC the trigger guard pin hole is 1/8".  A 1/8" roll pin typically measures 0.135".  I've had kits where the pins were either messed up or the wrong size.  The way I finally settled on assembling the trigger guard pin was to hold the pin with my fingers (I've got medium sized hands) and hit it a good lick with a plastic mallet.  Assuming I hit the pin and not my fingers it usually starts into the hole and I can then tap it in with a pin punch.  Also you might want to run a 1/8" drill (by hand) through the hole to make sure there aren't any burrs in the hole.  Good luck!

-YJ

ETA:  Ooops!  I didn't read far enough.  So you got it.  Good deal.  I finally see a question I know the answer to and you figure it out before I can answer it.  Oh well.