Heya @pchakour,
You mentioned you are upgrading to 7.6 -- what version are you upgrading from?
Out of curiosity, is the plugin you are working on in a public repository somewhere so that I'd be able to install it and test a few things out?
We've been updating the custom visualization infrastructure quite a bit over 7.x, so I want to make sure there aren't regressions that we have somehow missed, or release notes that are inaccurate.