Funnily enough I was just writing an edit for my post when your response came. I don't know a lot about coding but I looked into the .cfg file in GameData\ASET\ASET_StockRpl_IVAs\Patches and managed to make it work with the MK1-2 Pod for my needs. I just changed the beginning of the first line from "@PART[mk1-3pod]" to "@PART[Mark1-2Pod]" and that seemed to do the trick. Hope that's okay with you.
Also a few things I found odd:
while testing the interior didn't appear in the selection for the MK1-3 Pod's interiors either
It looks like CKAN just puts the folder for the replacements into the GameData folder, not into the ASET folder unlike when you install it manually