Thanks for all the answers.
I tried LittleStain's version and it works, too! I think it's a nice solution. Using Animation Frames wouldn't help me, i guess, since i want to use this for a mouse control like in diablo 2.
Also thanks to RamPackWobble for the answer, but i don't know how to open that public capx file, so it's not helpful until someone explains me how to open it (please do)
And just for the record: I have tried it with using a globale variable, just did it wrong ^^.