tagged pdf

We have a number of dynamically generated PDFs on our site that were created using iText 2.1.7. However, we also have a large number of users that have disabilities and use screen readers, like JAWS, to render our PDFs. We use the setTagged() method to tag the PDFs, but some elements of the PDF appear out of order. Some even become more jumbled after calling setTagged() !
This example was written in answer to the question How can I generate a PDF/UA compatible PDF with iText?
Does a PDF file have styles, headers and footers information as is the case with docx files that have separate xml files with extra information?
I am trying to create a document that conforms with PDF/A-1 level A. As long as I don't introduce a header or a footer using a page event, the code works fine. However, when I introduce text that is added at an absolute position, iText throws an exception telling me that the content I'm adding isn't tagged.
I know that iText can generate tagged PDF documents from scratch, but is it possible to insert alternative text for images in an existing tagged PDF without changing anything else?
I know that iText can generate tagged PDF documents from scratch, but is it possible to insert alternative text for images in an existing tagged PDF without changing anything else?
I am trying to create a document that conforms with PDF/A-1 level A. As long as I don't introduce a header or a footer using a page event, the code works fine. However, when I introduce text that is added at an absolute position, iText throws an exception telling me that the content I'm adding isn't tagged.