Well, I applied the kit.
Thank you Blackstridaaustria for sending it to me 
But the creaking noise is still here.
So the rear hinge is probably not in cause.
Btw I’m happy to have this kit installed so that the frame will not be damaged with time 
According to me the remaining possibility is the KS3 internal system itself.
I may try to expect a replacement of it under warranty (5 years).
What do you think after all these tests ?