Word IS correctly inserting your cover page! YOU have to correctly set the parameters for inserting the page. If you have no margins defined on the cover page and you insert the page into a document that is set up to have margins at (for example) 1.0" on all borders, your cover page is going to fit where you inserted it. So, you are going to have to create the page (where you want the cover to be inserted) with margins set at zero and adjust the remaining pages of the file accordingly (using a "section break" between the pages).