(I tried to use set! on the left of (append.......) but it doesn't work.
Thank you for your help.
g.
P.S. Another possibility that I didn't yet tried: if the scheme list is a structure made of couple of information, data + pointer, maybe I could put my information starting from the second element of the list..... sorry if I'm not very clear. I will try and then I will try to explain myself better.
P.P.S
To Andrew:
Yes Andrew, you're right. Instead of solve my problem by trial and error it would be better to read a good scheme book. I already started and stopped many times...... But I have some books on my (virtual) desktop that I will really read before or later
To Aaron: thank you for having reminded me the convention of exclamation point! I used it in my last code!