On a few rare occaisions I have pinned CA hinges too, but I use a slightly different method.

Instead of a toothpick, I use a straight pin (Or "T" Pin)

(Note: the folowing proceedure assumes the stab or fin is aproximately 1/4" balse. If it's not, adjust accordingly)

Push the pin up through the bottom of the stab until you feel it hit the hinge. Now carefully push it just through the hinge.

Once you feel that it has broken through, Stop! Now cut the pin with a pair of side cutters as close to the stab as possible (There will be a little nub of pin still protruding from the surface)

Now push the remaining nub just below the surface.

Voila! The hinges is pinned, and all that shows are a few pinholes on the underside!