ETTR (press set) and REC Key compatible?

[melimelo]

Still getting used to ML and questions/doubts keep coming...fortunately, the answer is almost always available in this forum... :-)

But one thing I have not found the answer to is the following:

I like to have ETTR always easily available (but not always on or auto snap) and therefore have set ETTR to "press set" (HalfShutter DC is either too "difficult for me" or not very smooth!!!)

However, when in Live View movie mode, set button is also used (at least in the 5D mark II) to start/stop video recording.  Therefore when set is pressed, ETTR does its magic but there is no way to record video.

So I figured that I could use the REC key feature to start/stop video. When I tried that configuration (rec key "ON" and ETTR "Set Button"), and half pressed  the shutter in Live View, instead of starting video, ettr sort of started to launch, then camera sort of freezes for miliseconds, then live view goes off and normal photo mode turns on...

Anything i'm doing wrong? any other way to have ettr "available" (not always on or autosnap) but at the same time being able to record video???