[RomainVL]

Finally it works perfectly, I only had to put avatars/usernames/age/... to the left :

Admin CP > vBulletin Options > Style & Language Settings; and set the "Use Legacy (Vertical) Postbit Template" to Yes (and save)

And now you only have to pute the code at the correct place in the postbit_legacy, otherwise it will show up under the cadre.

So find this line :

<if condition="$post['field2']"><div>$vbphrase[location_perm]: $post[field2]</div></if>

and add the flag code after

<!-- / flags start -->
<div>
<if condition="$post[field11]"><img src="images/flags/$post[field11].GIF"></if>
</div>
<!-- / flags end -->

and you're done.