I just did this with my Raleigh Twenty powder coat. I used a small straight blade screwdriver to knock the inside of the rivets off (inside head tube). Then used a tiny nail to make a divot in the center of the rivet, then drilled the rivets out.
[MENTION=381793]gugie[/MENTION] kindly provided me with the screw type rivets and I tapped those on, with no need to file off on the inside. Worked great.