X5 rear output shaft out from differential

[Doru]

Hello everybody.
I changed the 2 rear ball joints at the wheel carrier level, and after the install I noticed that the passenger side output shaft has come out about 1/4" from the rear differential. I noticed it this morning, when I saw some oil on the ground. Yesterday, after the repair I went for a drive, and all was good (apparently), but somehow during the repair, I probably pulled the passenger half shat out of the differential.

It's here in this picture from realoem, close to the differential:

.

The question is: how do I place it back? I couldn't find anything by searching/googling

P.S.: it's at the "reinforcement" level = part #2 - just behind it, where some sort of conical protection is. You can see the shining driveshaft between that conical protection part and the differential.

P.P.S.: here is a pic of the issue. How can I place it back?