Not a new Feature for Windows, to use an enterprise CA to create server certificates.
And Firefox added the possibility to trust those certificates ages ago – but still you’ll get an TLS-error-message (in German „Kein Verbindungsversuch unternommen: Mögliches Sicherheitsproblem“).
This is no Security-Problem, it’s just a problem of using stupid defaults causing people to waste their time and providing no little level of security, since a CA operated on my own is much more trustworthy than public CAs which firefox trusts blindly.
Solution
Open
about:config
and change
security.enterprise_roots.enabled := true
Disclaimer
Since i’m trying to get rid of Evernote, too anoying too often, i’ll start to document non-private-stuff here.