Roto, I have no personal experience with certification in Europe though we "imported" three Austrians for our first season and a Swiss instructor for our second season and I have learned much as how they go about it.
The Austrians went to a >Sports schule< a highschool where a half day of each schoolday is spent on the particular sport each student desires. Then they went to a >Sports-hoch-schule< for two years where there were no academic subjects that didn't pertain to skiing. Math, geometry, anatomy, etc. were taught because they are important in ski instructing and racing. When they graduated they were instructors.
The Swiss guy, short, stocky, wide tracked and so stable, a bulldozer couldn't have pushed him over, was dubbed the "Urmensch" the original human, by our ski school director Ziggy Baier. The reason was that, while skiing, he looked just like the illustrations of the evolution of man, the particular one just befor man walked totally upright. His long arms would hold the poles and they dangeled from his hands well below his knees and there was no way one could tell what made him turn, he just was always in this hunched over position. Not speaking English also complicated things.
Ziggy had a serious talk with him after seeing him lead his class down the hill. They looked like a long line of monkeys
Sorry that I have no particulars, just that even there, instructors still needed a sideline to make ends meet.