Are you saying that you want to "pose" a character for a still shot? or what?
For a G3 character use the 2D motion Key Editor in Stage Mode.
For a G2 character, in Stage mode, use any of the Motion Editor tools.
ALL Animation is done on the stage, that includes poses and any movement.
Composer Mode only builds the character, not animate it.
I still don't see what the problem is.
Give an example/pictures of what you are trying to accomplish if you want further help on this.
See my CTA Tutorials on the YouTube channel CTAStepByStep
Check out EZColors for CTA. The easy way to change Render Styled (RS) colors.