diff --git a/cpdfimage.ml b/cpdfimage.ml
index 4c1b285..72b6d53 100644
--- a/cpdfimage.ml
+++ b/cpdfimage.ml
@@ -518,7 +518,7 @@ let image_of_input ?subformat ?title ~process_struct_tree fobj i =
     | _, (Some Cpdfua.PDFUA1 | Some Cpdfua.PDFUA2) | true, _ -> true
     | _ -> false
   in
-    if process_struct_tree || subformat = Some Cpdfua.PDFUA2 then
+    if subformat = Some Cpdfua.PDFUA2 then
       begin
         let str = Pdf.addobj pdf Pdf.Null in
         let figure = Pdf.addobj pdf Pdf.Null in
@@ -532,7 +532,7 @@ let image_of_input ?subformat ?title ~process_struct_tree fobj i =
                                                        ("/K", Pdf.Array [Pdf.Indirect document]); ("/ParentTree", Pdf.Indirect parent_tree)]);
         Pdf.replace_chain pdf ["/Root"] ("/StructTreeRoot", (Pdf.Indirect str))
       end
-    else if subformat = Some Cpdfua.PDFUA1 then
+    else if process_struct_tree || subformat = Some Cpdfua.PDFUA1 then
       begin
         let str = Pdf.addobj pdf Pdf.Null in
         let figure = Pdf.addobj pdf Pdf.Null in
diff --git a/cpdftexttopdf.ml b/cpdftexttopdf.ml
index 90cc306..9922761 100644
--- a/cpdftexttopdf.ml
+++ b/cpdftexttopdf.ml
@@ -56,7 +56,9 @@ let tag_paragraphs l =
 
 let typeset ~process_struct_tree ?subformat ?title ~papersize ~font ~fontsize text =
   let process_struct_tree =
-    process_struct_tree || subformat = Some Cpdfua.PDFUA1 || subformat = Some Cpdfua.PDFUA2
+    match process_struct_tree, subformat with
+    | _, (Some Cpdfua.PDFUA1 | Some Cpdfua.PDFUA2) | true, _ -> true
+    | _ -> false
   in
   let pdf, title =
     match subformat with
@@ -92,6 +94,35 @@ let typeset ~process_struct_tree ?subformat ?title ~papersize ~font ~fontsize te
       let firstfont = hd (keep (function Cpdftype.Font _ -> true | _ -> false) tagged) in 
         [firstfont; Cpdftype.BeginDocument] @ tagged
   in
+    if subformat = Some Cpdfua.PDFUA2 then
+      begin
+        let str = Pdf.addobj pdf Pdf.Null in
+        let p = Pdf.addobj pdf Pdf.Null in
+        let parent_tree = Pdf.addobj pdf Pdf.Null in
+        let namespace = Pdf.addobj pdf (Pdf.Dictionary [("/NS", Pdf.String "http://iso.org/pdf2/ssn")]) in
+        let document = Pdf.addobj pdf Pdf.Null in
+        Pdf.addobj_given_num pdf (document, Pdf.Dictionary [("/K", Pdf.Array [Pdf.Indirect p]); ("/P", Pdf.Indirect str); ("/S", Pdf.Name "/Document"); ("/NS", Pdf.Indirect namespace)]);
+        Pdf.addobj_given_num pdf (parent_tree, Pdf.Dictionary [("/Nums", Pdf.Array [Pdf.Integer 1; Pdf.Array [Pdf.Indirect p]])]);
+        Pdf.addobj_given_num pdf (p, Pdf.Dictionary [("/K", Pdf.Array [Pdf.Integer 0]); ("/P", Pdf.Indirect document); ("/S", Pdf.Name "/P")]);
+        Pdf.addobj_given_num pdf (str, Pdf.Dictionary [("/Namespaces", Pdf.Array [Pdf.Indirect namespace]); ("/Type", Pdf.Name "/StructTreeRoot");
+                                                       ("/K", Pdf.Array [Pdf.Indirect document]); ("/ParentTree", Pdf.Indirect parent_tree)]);
+        Pdf.replace_chain pdf ["/Root"] ("/StructTreeRoot", (Pdf.Indirect str))
+      end
+    else if process_struct_tree || subformat = Some Cpdfua.PDFUA1 then
+      begin
+        let str = Pdf.addobj pdf Pdf.Null in
+        let p = Pdf.addobj pdf Pdf.Null in
+        let parent_tree = Pdf.addobj pdf Pdf.Null in
+        Pdf.addobj_given_num pdf (parent_tree, Pdf.Dictionary [("/Nums", Pdf.Array [Pdf.Integer 1; Pdf.Array [Pdf.Indirect p]])]);
+        Pdf.addobj_given_num pdf (p, Pdf.Dictionary [("/K", Pdf.Array [Pdf.Integer 0]); ("/P", Pdf.Indirect str); ("/S", Pdf.Name "/P")]);
+        Pdf.addobj_given_num pdf (str, Pdf.Dictionary [("/Type", Pdf.Name "/StructTreeRoot"); ("/K", Pdf.Array [Pdf.Indirect p]); ("/ParentTree", Pdf.Indirect parent_tree)]);
+        Pdf.replace_chain pdf ["/Root"] ("/StructTreeRoot", (Pdf.Indirect str))
+      end;
   let pages, tags = Cpdftype.typeset ~process_struct_tree margin margin margin margin papersize pdf instrs in
+  let pages =
+    map
+      (fun p -> if process_struct_tree then {p with Pdfpage.rest = Pdf.add_dict_entry p.Pdfpage.rest "/StructParents" (Pdf.Integer 1)} else p)
+      pages
+  in
     let pdf, pageroot = Pdfpage.add_pagetree pages pdf in
       Pdfpage.add_root pageroot [] pdf