You could try this, as noted upstream.

http://www.flyertalk.com/forum/10278141-post303.html

But it's probably faster and more reliable to walk; should be a brisk 10 minutes or less.

There's also an inter-terminal shuttle, again, as noted upstream that picks up downstairs.

I think with CO status for check-in at T6 you'll be fine. But I wouldn't tarry while enjoying the exhaust of the circling buses.