Merging multiple .docx is removing digital signature from signatureline

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C#

C#4.0

When I open the merged .docx it is requesting the signatures that were added in the SignatureSet. The problem seems to be in the Selection.Paste() function, but I haven't figured out how to fix it. The sign date is also removed.

This is the function that saves and signs each file based on user input.

// Save the file before adding signature.
oDoc.SaveAs2(saveFile);

                Word.Paragraph oPara3;
                oRng = oDoc.Bookmarks.get_Item(ref oEndOfDoc).Range;
                oPara3 = oDoc.Content.Paragraphs.Add(ref oRng);

                Word.Range p3 = oPara3.Range;
                p3.ParagraphFormat.Alignment = WdParagraphAlignment.wdAlignParagraphLeft;
                oPara3.Range.InsertParagraphAfter();
                oPara3.Range.Select();


                SignatureSet signatureSet = oDoc.Signatures;
                //Signature objSignature = signatureSet.Add();
                Signature signature = signatureSet.AddSignatureLine();
                signature.Setup.ShowSignDate = true;
                signature.Sign();
                
                oDoc.SaveAs2(saveFile);
                oDoc.Close();
                oWord.Quit();
                GC.Collect();
                System.Runtime.InteropServices.Marshal.ReleaseComObject(oWord);
                System.Runtime.InteropServices.Marshal.ReleaseComObject(oDoc);

Loop through the checked items and merge into report.

for (int i = 0; i < listView1.CheckedItems.Count; i++)
                {
                    string wPath = treeView1.SelectedNode.FullPath;
                    string checkedItems = listView1.CheckedItems[i].Text;
                    string getDoc = Path.Combine(wPath, checkedItems);

                    Word._Document copyFromDoc = mergeApp.Documents.Open(getDoc);
                    copyFromDoc.ActiveWindow.Selection.WholeStory();

                    copyFromDoc.ActiveWindow.Selection.Copy();

                    mergeDoc.ActiveWindow.Selection.Paste();

                    copyFromDoc.Close();

                }