Sprites from a .ccbi file not correctly positioned on iPad (sample project included)

Hi,
I have two sprites (a gray and a red one), child of a same node contained in a .ccbi file (created using cocosbuilder).

The red sprite should be adjacent to the gray sprite, without any gap.

On iPhone (and iPhone Retina) they are OK :

On iPad, there is an unwanted gap between the two sprites :

Here is a sample project (and the cocosbuilder files) that reproduce this problem.
http://pacolabs.com/public/ForumData/cocos2D/PositioningProblem/PositioningProblem.zip

I suspect that it is linked to the setContentScaleFactor of the Director which may not be applied as expected.
(a 2.0 hardcoded value for the iPad solves the gap problem, but the sprite become a little bit scaled, which is something I don’t want)

I must be doing something wrong.
How can I make the red sprite placed the same way on all the devices ?

Hi,
I still have the problem, and I cannot find a solution.
can anyone help ?
thanks.