Crude, but effective

.
I'm also using SC 2.9.2, and I just settled for flashing the EB01 touchwiz music player that adrynalyne referenced under patches in the
current SC thread. You're looking for "
eb01_twmusic.zip".
When you start playing a music file with this player while docked, you'll see a phone icon. Touch that icon and your audio is sent out the 3.5mm port in the back of the dock. Pause the song, hit the home key, and launch whatever audio source app you want to use, and all audio keeps routing out of the dock...
Granted, simply plugging a 3.5mm jack into your phone's newly-exposed port is probably easier

.
I also have the car dock and the same procedure works there.
I wish a simple preference setting was provided by Samsung for this - oh wait - Samsung hasn't provided %^&* to help us out with the accessories they sold us...