giorgio nicola wrote on Jul 26^th, 2011 at 11:44am:

If you want to hold altitude (I think) you have to set it also on the Flight Director panel

I rarely use the Flight Director panel. Last time I used it, I couldn't follow my flight plan. BUT  I think it had to do with me not having the FD on the correct setting at the time (like the AP was on NAV while the FD was on something like HDG). Another thing I encountered was that I couldn't track the GS when I had the FD on as well. I might be doing something wrong though, so I might need to experiment a bit more to find out.

Mark