unfortunately I haven't got any spare time these days to spend on your problem. Here's my advice, in the hope that it may be helpful: Try installing a fresh 3.9.3-based installation on a development server with the 'old' SIPS extension. It should work out of the box. From there, you may add the same debug checkpoints, and compare between your installation and this one. That should give you a clue about where to search the error...