about EditableMovie class

Well, the editableMovie class has been deprecated. Due to deprecation the docs are unavailable directly, but you can read them here.
Deprecated means that Real Software will remove it someday, but as of today (and probably a few more years) the class will be available and running. Just not forever. The reason is that Apple deprecated the old QuickTime APIs and they are not available for 64 bit..
I'm not sure about what way Apple is going with 64 bit. They have several frameworks for video playback. Like QTKit where we have a lot of classes in our plugins.
So I expect the old QuickTime classes in Real Studio and our plugins will continue to work in 32 bit applications. Even if editableMovie class is removed next year from Real Studio, our plugin still provides movie class extensions to do similar functions.
For 64 bit, you may go and move to QTKit. It offers some features, but not all.
In general, if you are missing something, please email us. Maybe we can add it quickly for you.