If it were my car, I'd first try to push up on the bottom clam shell that's under the steering wheel column. If that doesn't change (no squeak, or a different sounding squeak), then try pushing down on the top clam shell.
If nothing else, it will remove the clam shell from the test equation.
Is the squeak just from turning the steering wheel left to right, or is it also from moving the steering wheel up & down, in & out?
2000 740iS. MKIV, 16x9, DDEs controlled by Euro fog light switch, reversed steptronic +/- pattern, paddle shifters, clear corners, Basslink, iPod video with stereo audio, TV tuner, gauge rings, ///M pedals, backup camera with 'on demand' switch, quad brake lights, Dinan engine & tranny software, windows/sunroof close via remote.
2003 540iS. MKIV, 16x9, PDC, CWP, TV tuner, backup camera with 'on demand' switch, paddle shifters, windows/sunroof close via remote, iPod video & audio.