I have to say its pretty dissapointing if nobody has a solution to this problem!
So here my workaround!
I used zooXferAnim to safe the animation into a file which i then can import in a different file and then copy my keys on a seperate animation layer.
First of all i needed to delet my character set because zooxferAnim does not work with subcharacter sets.
After creating a new character set without subsets you can use that set to export the animation keys in a kind of xml file.
This file can then be imported in a different scene but only on the same rig with exactly the same controls and character set.
Also i needed to use an older version of zooxferAnim because the newest version didn't have an export function. (maybe it has but i couldn't find it!)
If someone has a better solution i would be happy to read about it.
Greetings Braggart
PS.: If you have any questions feel free to ask me.