Thank you very much.
This is a beginning... But not exactly what I wanted. Maybe there even is no possbility at all to do all the stuff I 've wanted to be done automatically.
I have some animations that need to be rendered from the same point of view. And I don't need every frame just about every 5th or so (for creating an animated GIF).
So the perfect solution would be: I press an "button" in Anim8or. The camera is set at the correct position. The background would be colored like I wish. The scene would be rendered (and saved). The animation would go 5 frames further -> next rendering. Ans so on...
I could write an external program to simulate mouse and keyboard events. But I think it would be quite more elegant to write an ASL script with this abilities.