To fix the 'no ending' issue on the HD beta all you have to do is the following.

Go to the folder you installed SC2 HD in.

Go to the /content/addons/ subfolder.

Delete the 3dovideo.zip file.

It doesn't even contain the 3do videos, but, for some reason prevents the intro and ending.

I figured this out while attempting to install the 3dovideos so they would work with this version of the game.

They work fine on the UQM version, but, the HD version does not seem to work with the 3dovideos.  Additionally, if you have them 'installed' it won't play the opening slides or the opening video.

So, good luck and hopefully they fix the issue with the videos eventually.  Although, I must say I prefer the slides anyway.