How do I disable the popup when I connect my phone to my PC via USB? How do I disable the popup (the one asking me if I want to mount my SD card) when I connect my phone to my PC via USB?

I've been told it's a feature of CyanogenMod but I can't for the life of me find it. I'm using CyanogenMod 7.0 RC, with Android 2.3.2.
If you enable USB debugging in the Developer options, the phone's "USB Connected!" screen doesn't popup anymore :)