There's an action part for setting the object visibility. If you want to script it with Lua then you need to script 2 different fields, or use the new to() function, which may or may not work in the current public build.
I recommend using the action part as it's just simpler all round.
example of to function... Objects["annoying_oap"]:to(3000, {Visibility = 0}) -- fade object "annoying_oap" to 0% opacity over 3 seconds.
What do you mean by a sleep function?
P.S: why is the title of thread in English, while the text is in German?
