Unfortunately, there is a bug with the AP pitch unless you have FSX Acceleration.  The AP pitch control does not work under FSX SP2.  There is a "fix" that you can download from the Captain Sim support area, but it caused me more problems than the issue it was supposed to fix.  

I had to purchase and install Acceleration to get this working right.  Otherwise you will have to control pitch manually.  The AP will hold a pitch and altitude once you get stabilized, but that knob you are supposed to use to change the pitch will not work.