Since it's a matter of patent licensing, unless Firefox licenses the patents MS was unwilling to, they'll have to break Firefox (and Mozilla) the exact same way if the patent holder goes after them.

This is one of those things where the only workaround is to get the web pages re-written, because the patent is on the "process", not the details. In other words, auto-starting embedded content violates the patent.

The workarounds on the web page end involve javascript and even uglier things.