I understand what you mean. With the type of front panel that you are using, it is very difficult to get the right configuration.
Intel publishes its audio header spec on the document:
But i would imagine that the front panel supplier would be the tower case supppplier, it would be good to check with them.
I know many cases where due to wrong connection short-circuit the board.
I have always used the one like this:
Note:AC97 does not work on many new boards.
All the best,