Forgive my naievity but isn't the standard procedure on entering cloud below safety altitude to max perform climb to safety altitude. If that climb takes you into controlled airspace then Mode 3A/7700 and call on 243.0 or 121.5. To do less is surely negligent. From what I can glean the aircraft does not appear to have been in max performance climb mode at the point of impact although I do recall John Nichol trying to make the point in Panorama (I think) that the IFF was set to 7700 - he was trying to suggest this meant theuy had a technical problem but as always there is more than one possible explanation for everything!