I finally managed to fly with APM on Sunday. Here are some photos and a video of loitering. Well, it was flying a pattern which first looked like a figure 8 and then the olympic rings. Any idea why? Will check everything again and fly a real mission when I can.
Preliminary conclusions: Manual mode is good, stabilize is very convincing, FBWA and FBWB work, loitering must be checked. PID parameters appear to be reasonable, no sudden movements.

It was awesome to have the model fly with me hands off for the first time!

The setup:
Reichard Proxima II glider, 2,78 m wingspan.
HS82MG AIL and FLAPS, HS65HB ELE and 9g cheap servo for RUD.
Dymond AL3548 outrunner 630 watt, 900 Upm/V and 60A Dymond regulator.
11,1 V 3300mAh LiPo battery
13" x 6,5" folding propeller

Radio:

Futaba T8FG with RH6008HS RX
Ch1: AIL with Y-cable
Ch3: Motor
Ch4: ELE
Ch5: RUD
Ch6: Flight mode control
Ch7 and Ch8: Flaps, not connected to APM but directly to the RX.

APM:

APM, IMU, Mediatek GPS MT3329, XBee 900MHz wire. Powered by a separate 1000mAh LiPo at 7,4 V (solder jumper removed).

Portable PC ASUS Eee 1000H with XBee 900MHz&duck antenna and HappyKillmore's GCS (that I can't look at when I'm flying anyway).

FlycamOneIII

Next improvements to be done are:
Connect the airspeed sensor.
Find a better way to mount the APM and associates under the hood whilst maintaining access to buttons, connectors and view of LEDs (transparent hood, holes).
Sort out the chaos of servo-cables in the fuselage.
Variometer based on a high precision pressure sensor, I2C/SPI.

Other issues:
Flaps are controlled manually on two separate channels to slow down for landing. It would have been nice to have differential ailerons, but I understand it's a matter of priorities. None of the other mixes (e.g. butterfly) will work because of the y-cable so we might as well accept to live without them in the APM domain, for the time being.

The model is quite beaten up, it has 55 hours of flying on it and a few crashes too. A brand new copy sits in the basement and will be used to build a perfect Proxima with APM when all tests and trials are completed. I will come back to you to discuss particular technical issues in the appropriate sections of the forum.

Cheers from
Parapendioper, Italy.