Warning tone volume adjustment?

[cdr]

I just picked up a new 2009 X5 (E70), and am trying to figure out how to lower the volume of the initial warning tones (seatbelt, freezing temp, etc...). I have seen in other posts a method best described by "Menu-->Settings--->Tone/Volume--->Warning Tones" but my vehicle - or perhaps more specifically, the version of iDrive on my vehicle (with Nav) does not have a "Warning Tones" sub-menu. I have even tried the volume adjustments (steering wheel & knob on stereo) while tones were being played, with no luck.

I stopped by my dealer for something unrelated and asked the sales guy (who was otherwise very knowledgeable) and he was mystified. Has anyone else been able to solve this problem with a recent model X5?

Many thanks in advance.