After numerous problems and extrusion, I decided to create my own extruder design. 
I got recovered a few pieces of the original extruder. However, I add an M3 screw and threaded rod M3. Some holes are threaded to ensure the mounting.

The main original extruder problem with few next points: 1 / clearance is too low such that the extrusion is complete. If the filament is 3mm it's ok  and 2.85mm it's no ok because not force sufficient spring. If the filament is 3.1mm it's no ok because the jam filament in a extruder.
2 / The pin hole admision is small because that friction is important. I change in my version of a long tube in order to guide the wire and 0.2mm diameter additional. 
3 / In the original, the passage of the wire is done through an "L White" It turns out that this mode generates additional constraints on the filament. 
4 / The Location of the ball bearing is not optimum. 
5 / The assembly and install is not simple. The flange that hold the spring...

For all these reasons, I can you get online the picture previews. The part replace is in a test for long printing.

Do not hesitate to tell me what you think and if you have had the opportunity to test. 
Note: When you reassemble the motor of the extruder, really be careful not to catch the sons. I had this mishap and I had to replace the wire.

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Updated 20 / 02 / 2014: I change the ring which is against the articulated arm. It is better kept and fulfilled its role now.