The principle aim of OFPEC is to help editors with editing related problems. We seldom provide ready-made solutions because it defeats the purpose of educating the Community. As the saying goes: give a man a fish, he'll eat for a day; teach a man to fish, he'll feed his family for life.
Thus, if you looked at the second link provided above you'd see a method used for raising the standard targets, namely by setting their damage to 0. So if you place a target on the map, and in its init field set the damage to 1 so it's down, then place a trigger over the target and group it with the player, when that player gets into the trigger area, you can set the target's damage to 0 so it pops up.
This is all untested, so it may not work, but it's up to you to test it to see if it works, and if not try something else.