thispatcher inside bpatcher / window mode

Hi guys !
I’m just beginning in M4L, and I’m exposed to a new problem, maybe a limitation, I don’t understand.
I’ve got a bpatcher containing a patch, which I would like to make grow in a window at will.
When in bpatcher box (in the main patch), just a button is visible, which one is connected (inside the subpatch) to a thispatcher object via the “front” msg.
This works, the window appears.
But all others commands won’t work (window size, title, float…), allthought it is working correctly when I open the patch directly (not via the instance in the bpatcher).
I hope I’m clear enough… don’t know if it is a limitation, or if maybe the thispatcher object is talking to the bpatcher BOX instead of the subpatch it contains itself… In this case how to point to the patch, not naming it expressly because a term I will have a lot of instances in my main patch (maybe 50-60).
I’ve made a simplified patch of this to illustrate the problem

Thanks in advance :)
Fred