What version of Acrobat are you using? What Acrobat command are you using to convert a web page?
1) Acrobat X Pro - as stated on the first line.
2) Create PDF from Web Page. Also Pages-More Insert Options - Add to PDF from Web Page. Both produce the same result.
In the Create PDF from Web Page dialog, click on the Settings button. Click on the Page Layout tab. You can change the margins and page size here.
THANK YOU very much! This seems to work with appending a web page as well.
This is in fact documented in the Acrobat Help file - see page 74.