ooh thank you very much for this advice!!
I could use this! however I don't think I can do that on this model..you see, I want to make a mobile and I know have the model done and have to start with the buttons..

I tried the booleansthing but as you said, I need to ad more edges (cuts) so that it can become a clean mesh but If I do that than te model start to change the way it's not pretended to..
Can I prefend this ?

I attach a image to let you see what my problem is..
maybe you or anyone has an Idea how I could make the buttons???

I love the way people helping me and others at simplymaya! bravo!!!