I personally have never done it, but here's what I could find in the manual ('05 STS). I couldn't find anything that said the DIC switch assembly would pop straight out of there on its own.
1. Pull outward on the center trim in order to release the clip retainers.
2. Remove the trim from the instrument panel.
center trim.gif
3.Pull outward on the cluster trim in order to release the clips securing the trim to the instrument panel.
dash1.gif
4.Disconnect the electrical connectors.
5.Disconnect the aspirator tube.
dash2.gif
It doesn't say whether the steering wheel is in the way or not. At least if you do it this way you could tell the rest of us if the switch assembly would have popped out without removing the trim.
