Juhana,
Just a side note - I listened to your sample songs and really think you are a great composer. I've listened to other people's samples now and then but was never really impressed. Now I am. I am going to bookmark your site in my browser. You are too cool! -Mike

Geniesoft's Overture has this feature. Select a note by clicking on it and press R to convert it to a rest of the same value. Or press a number to convert it to another note weight (1=whole, 2=half, 3=3rd, 4=fourth, etc).
-Mike

I thought that was standard notation practice.
-Mike