had been / had been doing + since

[Kynas]

Hallo, ist es möglich ad been / had been doing + since zu verwenden?

Also "before he did it, he hadnt done / hadnt been doing it since 1969" Bevor er es gemacht hat, hatte er es seit 1969 nicht mehr gemacht.

[tiorthan]

"had not done it since ..." - Ja
"had not been doing it since ..." - Lieber nicht, das Continuous ergibt zusammen mit der Negation und dem "since" keinen wirklich greifbaren Sinn