AllanR,
I'm very grateful for your help. I spent some time messing with some variables and finally managed to get the result I wanted. In the end I learned a lot from it. You have been an excellent teacher, and I apologize for my inexperience, but as I said, now I feel a bit more ready for new discoveries. As soon as I finish the game, I'll send you a copy and your name will be in the credits as an important contributor. I know this does not mean much, because I do not know if you will like the game (or other people will), but know that your help meant a lot to me. Many thanks once again!
You should write a tutorial, you are very good with that! If you have any material posted on some blog or on the Internet I would like to see it.
All the best for you!