Awesome! Thanks. In fact I did search the forums, but I didn't think of searching in english. Now I know better
Great! do a favor and post the answers here if you find them, so that it will be more available.
So that is the answer that helped me:
Richtige Antwort von martinr84659894 am 06.07.2016 04:12
Same Problem here, but also a solution!
In AFX CC2015.3 (13.8), the german shortcuts have been changed, or are bad implemented. However, if you still have the shortcut-list from version CC2014 (13.2) or CC2015 (13.5 i guess), you can copy it with a bit alternation to the new install location.
If you don't have one of the previous shortcut lists, or don't want to follow the steps below, just download and unzip this shortcut-list-file and save it to "C:\Users\USERNAME\AppData\Roaming\Adobe\After Effects\13.8" (Windows). On Mac, search for "Adobe After Effects 13.8 Win de_DE Tastaturbefehle.txt" and save it there.
The long way:
1. You need the old shortcut-list.
On Windows it's located in: "C:\Users\USERNAME\AppData\Roaming\Adobe\After Effects\13.2". I don't know where it's on Mac, but you can search for "Adobe After Effects 13.2 Win de_DE Tastaturbefehle.txt".
2. You need the new shortcut-list.
Go to "C:\Users\USERNAME\AppData\Roaming\Adobe\After Effects\13.8" or search for "Adobe After Effects 13.8 Win de_DE Tastaturbefehle.txt".
3. You need a new, empty text-file.
Copy the whole text from the old shortcut-list (13.2 or 13.5) to this file.
4. You need to compare the two shotcut-lists from step 1 and 2.
I did it with this tool: Qualidator Text Diff/Vergleich .
5. You need to manually update the new text-file from step 3.
Look at the green and red lines in the tool from step 4 and make the changes in the new text-file from step 3. Some lines must be added, some removed.
6. You need to save and rename the new text file.
Save it at the location of the new shortcut-list ("C:\Users\USERNAME\AppData\Roaming\Adobe\After Effects\13.8") and name it "Adobe After Effects 13.8 Win de_DE Tastaturbefehle.txt"
Thanks to the non-existing-shortcut editor in AFX, it's easy as that.
Thank you Martin hopefully users will find this useful.