Conversion of PDF to XPS bookmarks (headings/pages)

After conversion from PDF to XPS (using pdftron.PDF.Convert.ToXps()) are all bookmarks directed to pages. But in original PDF they were direceted to headings (text anchors). Is it problem of conversion or limitation of XPS format?

It is a limitation of of XPS format. XPS spec only supports bookmarks to pages. So we are mapping to a closest possible destination.