Adding wp_editor to custom metabox

Unfortunately you can’t yet…

see this trac ticket: http://core.trac.wordpress.org/ticket/19173

In particular it seems that:

The problem is that TinyMCE, once initialized cannot be moved in the DOM, or rather the browsers cannot handle it being moved. That’s why the errors are so inconsistent in different browsers. Moving the postbox triggers this. Some browsers/versions handle that better than others as @ocean90 mentions above but generally the editor textarea and iframe shouldn’t be moved.
azaozz