I'm using VMComix's excellent fully rigged Porl character (https://www.blendswap.com/blends/view/14445) to experiment with character animation and have found all the sliders in the N menu that allow for animating common movements like making an open hand into a clench, etc.
However the character also has facial expressions - I'm trying to get him to go from basic facial expression in frame 1 to 'Jaw Drop' in frame 20.
I only seem to be able to activate the Jaw Drop from the Graph editor by switching type to 'Scripted Expression' and Expr to 1. However there doesn't seem to be any way to keyframe this.
I'm a Blender amateur and I get a feeling I'm overlooking something incredibly obvious .... any pointers would be greatly appreciated.