[sword-devel] HowTo: create ztext module?

[L.Allan-pbio]

I'd appreciate a hint or two on how to create ztext modules. (Or a 
link to documentation or previous list post on this).

I've been able to create plaintext modules for Bible texts, 
commentaries, devotionals, etc. that the rawtext driver can read, but 
I'm fuzzy how to create a ztext module that has book-block zlib 
compression.

Are there command line settings for the imp2vs and/or imp2ld console 
utilities, or is this controlled by the MyModule.conf file? Is there 
an extra step? Am I overlooking something?