DV Info Net - Exposure drifting with new software

Pardon the basic question, I've read the manual and I am still confused....
My camera has the new firmware (ver. 1.0.7). I'm using manual Nikkor lenses and set the camera in M manual mode, center weighted average metering mode. ISO is set to 200, shutter set to 60.
When I switch to Live View the camera goes into an autoexposure mode, changing the ISO rating as needed. When I select an area I want properly exposed and hit the AE switch the exposure locks.
So the first question - is there a way to turn off AE once it has been touched? I know I can select another are to meter but I would rather turn it off and on at will. SO far the only way I have found is to go out of Live View then back again.
Based on my shooting style ( and this camera is so different this is subject to change by the minute) I'd like to set my basic ISO depending on the situation, then set and lock my shutter speed (probably at 30 or 60), set the aperture manually and use the rear control dial to adjust the ISO as needed. Is this possible?
The camera makes such great images it is hard to put it down long enough to really study the manual, and I don't find the manual all that logically organized anyway. Is there a clearly written book similar to Doug Jensen's Vortex books for the EX cameras?
And lastly, thanks to all who preceeded me with questions, and especially to those who contributed answers - this is an astounding wealth of information!