Wesslen, I'd suggest to drop LibSharedMedia-3.0 and pick up SharedMedia in its place. This works well for me, and displays my custom Mymedia fonts just fine.
SharedMedia is a collection of assets, LibSharedMedia is the library that makes it available to other addons. It's not possible to drop LibSharedMedia and still use SharedMedia in a meaningful way. You're using LibSharedMedia too, only it seems to work for you...
I'll investigate further another day.