Terminology of notation: the 4x4 board has 4 partial boards A, B, C, D which are arranged clockwise, starting in north-west like this:
Tderz: I give the 4 different orientation of the partial boards:
For easier copying the board is: (in editing mode it looks ok) 
X O . X
could be annotated like this
turning all +90° => forbidden position, but
which has m-symmetry because all symmetrically arranged subboards have too: notation must be (and is):
: copying for editing seems to make no sense here
ferdi: I certainly don't know what this is all about, but it helped you to find the solution ;-)
Tderz: Ferdi, I only wrote down the notation , because I thought that there would be many solutions, and wanted to streamline and classify the flux of incoming duplicates. Now I think that there won't be more than those with a 4-block in the center, because of the legality problem.
Thanks for the problem!
Tderz: Speaking of a 4-block in the center ...
Shortly after adding the 4th partial board, the 4 stones must be captured.