Ubuntu / Apple :: Screen On Display Entirely Black - External Monitor Never Becomes Active

Just did a fresh install of Natty B1 (previously had alpha 2).. I noticed this issue w/ A2, as well.. plugging in the exterminal monitor (via mini-displayport-to-vga connector) will do the following:

1) turn the screen on the laptop's display entirely black (but not turn it off).. i can move and see the mouse cursor.. but everything on the window appears to not rending or "painted" black..

2) external monitor never becomes active..

the only way to recover is to kill/restart X or reboot after disconnecting the extmon.. having extmon plugged in from boot produces the same results (and it doesn't seem to ever become active during boot up). sometimes this won't happen right away if i plug in the external monitor.. but opening the Monitors system prefs dialog will definitely cause (or detect displays) ,etc I waited to see if the issue would fix itself w/ the beta update, but it hasn't.. Any other 8,1 owners out there that can verify this issue? My (totally uninformed) guess is that it's due to differences in the display/gfx hardware and thunderbolt integration(?)

(I've seen a verification verifications of working-out-of-the-box.. but they were from 8,2 and 8,3 owners (which have discrete graphics cards))... If anyone's gotten this to work with some config stuff, I'd love to see that as well (since the wiki page for 8,1 says it works ootb). If someone could let me know where I should look to capture error output when the above issue occurs, that would be awesome.