More animation options

Is it possible to edit the properties of loop animations? For example, deciding when it starts and stops (possibly, slowly), instead of making it run all the time? I am currently trying to make a vinyl-like music player in KLWP, and I'm having some trouble since I don't know how to make a realistic animation. I want the "vinyl" to start slowly, and this is possibile using a rotate animation set to "normal", but after that, I don't know what to do. Setting another loop animation and making it start after the normal one has finished could work, if only the loop animation resets when it's not playing. But the animation keeps running and there's this "jump" and it just doesn't work.