The UE3 documentation is really the reference for UE3?
I am surprised about the quality of chapters like:
Is there an alternative documentation reserved for licensees? I am just asking (I know UDK is free)
As noted in the first paragraph of that article, that is a brief technical article for programmers. The link in that paragraph takes you to the User's Guide which is more useful for actually performing those processes.
UE3 simply is made so well and elegant that you do not need a lot of documentation.