Are you exporting from Poser, back into Poser, or to some intermediate app?  What exactly are you exporting?  How are you exporting it, with what options?  Your goal is to get your character transportable to other people, right?  I don't think exporting to OBJ is going to help you at all, the reason I think you'd want to do that is just to get it into another app.

As I understand it - and be aware my understanding may be quite poor :) - one way to get this to work is:

• Save a pose file that includes morph channels - you'd think body transformations would get scale changes too, but it doesn't.  This will also leave all the zeroed channels in the poze file, which you may not care about.  I wouldn't, particularly, but if you want to you can trim them out with some editor, possibly MAT Pose Edit as suggested.  Since you're going to zip the file anyway it will compress down quite small.
• Write a second pose file by hand that is modeled after the attached example, with a block for each bodypart that requires scaling and a sub-block for each dial that needs to be set.  It took me a few minutes to figure out the syntax but this works.

When you distribute, just have the user load both pose files as desired.  If you are seriously dead set on learning ERC to do this, more power to you, you can bundle all this together into one pose file I suppose and include the ERC channel configuration stuff (if it was me I'd not bother).

*note the attached "jpg" is the pose file, just rename it and remove the .jpg and place it wherever you like in runtimelibrariespose

My Freebies