Insert this code in HTML mode.
TEXT MIDDLE and LINK will be missing on save. (Must activate multimedia plugin)
I have tested it in 1.9.10 and 1.9.11+
But it was working in 1.9.7
I think the regex are incorrect in filter.php but they seems to be OK in moodle 2.0 branch
I moved it to "major" cause it breaks something that was working before..