[xwiki-users] video tag again

I'm using <video> tag on old XWiki 2.7 with 1.0 syntax, though I cannot to get it shown on XWiki 5.1 with 2.0/2.1 syntax. Sergiu said in http://lists.xwiki.org/pipermail/users/2011-July/020245.html that {{html clean="false"}} should be used, but it still filters <video> tag out... Valdis