It should work. A value of zero, is a value of zero. Whether you set that value through the Poser interface, or by editing the cr2 in a text editor is irrelevant. For a conformer it is the 'initValue' that is important, not the 'keys' value, hence the need to ensure that Memorized state of the channels is set to zero. The "Zero Figure" command in the Joint Editor will zero all the rotation channels in the figure. That can still leave translations of the hip and Body to be zeroed (in other parts translations will normally  be zero, if IK is off). There is no easy way (that I know of) to ensure that the all the scale channels are set to 100%  (more correctly 1.000 internal value), but they usually are already .