[O] Trouble with ordered list start number

[William Beard]

Hello,
I see in the manual
http://orgmode.org/manual/Plain-lists.html
that with ordered lists, you can for example start one with the number
20 by starting the "text of the item with address@hidden"
I assume this means I can just have a newline that looks like this

address@hidden some text for this item

and hit M-Return after typing the text for the item, and have a `21. '
appear below it. But when I do, it gives me the top header (`*')
instead.
What am I doing wrong?

Thanks
Chris

(Org-mode version 7.4)