Right click and copy the video address in your browsers address bar, rather than using the YouTube embedding command they offer. Hit the 'Insert/edit embedded media' button and paste the address in, Flash is the default selection so go with that and hit 'Insert'. In your Post Reply box a frame with a Flash logo in the centre will appear, finish your content and do the calc etc. 

Let the page sort itself out, the video may not appear immediately, and don't use the back button to navigate away from thread as this can cause the post to not stick if done too soon.

This vid was embedded using what's described above: