If you don't have a bookmark for two first pages of these two documents in your composite document, you can create them manually. Just go to the first page of your first document that is missing a bookmark, then click on the "New Bookmark" button on the bookmarks pane:
Or, use Ctrl-B or Cmd-B to create a new bookmark. By default, the bookmark will bring you to the active page at the time the bookmark was created. You can change that by right-clicking on the bookmark and changing the action.
At the time you create the bookmark, the bookmark text will be editable - you can name your bookmark appropriately. Now the only thing left is to drag and drop the bookmark into it's correct location in the bookmark hierarchy.
Karl Heinz Kremer
PDF Acrobatics Without a Net
PDF Software Development, Training and More...
http://www.khkonsulting.com