i found the solution for my problems 
twi new occured:
- i need an invisible actor stirring up the water. but if i set it to hidden in game or apply an invisible material to it, the water isnt moving anymore at all. Is there another way make the actor invisible ?
- i can set planar reflections on and off. Is there a way to control the power of the reflection ?
kind regards
this is adding so much to my game ! thx a thousand times again !!!
kind regards
stucki