As far as I know (and I don't know much) the purpose for nickel is to make the strings smoother/softer for the fingers, but there may be other purposes that relate to the sound.
Nevertheless I find the nickel free strings (Rotosound) on my electric guitar quite comfortable and good sounding and since I also found bass strings I just thought that it might be possible to get some for the acoustic as well.
Apparently they are not invented yet so I guess I have to go on suffering for my art
Thanks a lot for your responses anyway.