Set up heading numbering as discussed at
http://shaunakelly.com/word/numberin...g20072010.html. Then create body text paragraph styles, which you may call "Item 1," "Item 2," etc. (corresponding to your example). Make sure that "Item 1" is based on Heading 1, that "Item 2" is based on Heading 2, etc. For the "child" styles, change any settings that should be different from those of the parent heading styles. Numbering will be inherited.