I have been trying to do the what your talking about and sometimes InjMagic does include the custom morph, but it is not reliably. To make things worse, the author sold InjMagic to DAZ, and now the author does not support it and neither does DAZ so I guess it is dead-end software. DAZ Injection Pose Builder also will not insert custom morphs, although there may be a way to make it do so, I have read somewhere. I don't know enough about editing Cr2s to do it that way, although I am learning. Good luck and I hope somebody answers your question with an easy simple solution so I can use it too.