Okay, I've got a bit of a weird issue with my custom industries and I'm not sure how to fix it. Basically I'm not able to install the special items that I've got set up; the basic setup for the industry is very similar to the default Heavy Industry setup, with some specific stuff to account for the industry in question (Modular Fabricators) being able to be changed to a number of specialized sub-variants, for which I've got a number of yet to be tested special items which should hopefully be usable to start the process of upgrading the facility.
However, the Fabricators lack the option to install special items, being limited to story point linked output improvement, adding AI Cores, and shutting it down; it's not very clear why this should be the case, since the game is definitely finding the special item data (and indeed, I had to set up localized versions of GenericSpecialItemPlugin and ItemEffectsRepo in order to avoid getting Null Errors) so I figured I might as well ask here and see if anyone had any ideas. It's a little hard to be specific when it comes down to it though, since the game isn't giving me a lot to go on.