I don't use a command to load the modules mate.
I made a custom kickstart 3.9 ROM that includes all the patches from BB3+BB4 (Cosmos exec included along with graphics.library from PeterK).
Then... I only have to kick the new ROM and voila.
Try LoadResident as Cosmos said, I remember it worked just fine pre custom kickstarts on mine.
Is it relatively straight-forward to create a custom rom image?
I've got a Deneb to put in my A4000 so I want to make an up to date rom with Cosmos and Peter's new libs too.