Another case of "couldn't you've told me BEFORE I started working on this?"

I'm making a training in Unity3D for a client, and they want it to integrate with their learning management system (LMS).
I made a simple SCORM package that gets the userID and then uses a custom URL scheme to launch the app with the user data from the LMS.

Tested on multiple platforms, all works perfectly fine.

Than, during a meeting, some says they "can't download it". I ask "which browser are you using?" and he says "I'm using the LMS app."
... the LMS has an APP?

So I start figuring out ways to launch the system default browser from within a app's embedded browser, and nothing so far has worked.
target=_system, nope.
all kinds of weird javascript shenanigans, but the LMS APP browser just blocks everything.
Probably to protect students from malicious software that could be injected in courses, but now I'm stuck trying to find a workaround for this too.

But what sucks the most is that this happened DAYS BEFORE THE DEADLINE!
Well, at least the deadline won't be my problem anymore soon.