Centering a table cell in wysiwyg editor does not work or is ignored

If you try to center a table cell in the wysiwyg editor it has no effect in FF and works in IE but is then ignored by the HTML to wiki conversion process.

We could generate this

{table}
A| B
{style:align=center|type=div}1{style}| 2{table}

or extend the wiki syntax. See bug XWIKI-2539