I went to the Y-end and took more photos of the cable stand. These revealed that in-vac pin #13 is connected to the shield of the cable (P.2). This in-vac pin #13 corresponds to in-air pin #1. So in the end, we bunch the pins in the following order.
| In Air |
In Vac |
| Pin #2-7 |
Pin #12-7 |
| Pin #8-13 |
Pin #6-1 |
| Pin #14-19 |
Pin #25-20 |
| Pin #20-25 |
Pin #19-14 |
|