How to embed video in blogs, pages etc.

I'm having problems embedding video (e.g. from youtube, vimeo) in  blogs & pages. I've read a lot of discussions about the possible impact of TinyMCE, about having to click on add/remove editor before pasting code, using different browsers etc. etc. but nothing seems to work. When I paste the embed code I can see the video until I save (publish) the blog article. After that the video is replaced by a link to the source.

I have installed Elgg 1.7.8 (hosted on Arvixe) and enabled the "embed" plugin. What am I doing wrong?

A lot of the discussions seem to have been conducted quite some time ago so I hope that means that if there was an issue it has been solved since...