Erroneous importing of office documents with lists begining with specified numbers

For some office documents (depending on how they have been authored) OO server generates ordered lists like below:

<ol start="4">
  <li> item1
    <ul>
      <li>sub item1</li>
    </ul>
  </li>
</ol>

There are two problems with this type of lists:

1. The 'start' attribute of the <ol> tag has been deprecated in xhtml and there is no inline css solution available to for this attribute as mentioned in http://www.w3schools.com/TAGS/att_ol_start.asp. The only possible solution involves an embedded css stylesheet which is hard to implement in default html cleaner http://www.arraystudio.com/as-workshop/make-ol-list-start-from-number-different-than-1-using-css.html

2. The attribute 'start' get's repeated into each nested <li> element because of http://jira.xwiki.org/jira/browse/XWIKI-3067

Although fixing XWIKI-3067 would solve this problem, we still have to decide what we are going to do about the 'start' tag because that is not valid.