I don't know if someone brought this up, but with the initial firmware on the 5Dmk2, controlling audio levels manually is not possible. You need to update the firmware to version 2.1.2 to do so.
Over here: http://www.usa.canon.com/cusa/support/professional/professional_cameras/eos_digital_slr_cameras/eos_5d_mark_ii#DriversAndSoftware
But do read this on page 2: http://www.learn.usa.canon.com/resources/articles/2011/eos5dmarkiifirmware_article.shtml
Oh, and if you're still looking for a post guy, I'd like to offer my services!