When the first night of Chanukah falls out on Motzei Shabbos

This year 5773 or 2012 has the first night of Chanukah falling out on Motzei shabbos. One is allowed to set up the Menorah before shabbos so he can light it immediately after havdala according to most customs on Motzei shabbos. There is a discussion among the poskim if one is allowed to be mavdil with the Ner chanukah, we are not noheg to do that, and most have the Minhag to make havdalah first and then light the Ner chanukah. On shabbos Erev Chanukah one should be carefull  when eating shalosh seudos to have a kazayis before shkiah in order to avoid a halachic problem of saying al hanisim by bentching.