Rob Wisenant has a tutorial for creating INJ and REM morphs by hand:
http://rbtwhiz.com/rbtwhiz_rScript.html
And this tutorial is for the creation of the actual deltas:
http://rbtwhiz.com/rbtwhiz_deltaInjection.html

Alternatively, Daz sells 2 different programs which help you create these:
Injection Pose Builder 1.5
Injection Magic
I personally favour the latter, but it's a matter of taste really.

Hope this helps :-)

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"you are terrifying
and strange and beautiful
something not everyone knows how to love." - Warsan Shire