WordApplication->Connect();
pDoc = WordApplication->Documents->Add(Template);

pDoc->Bookmarks->Item(OleVariant(StringToOleStr("DocNum")))->Select();
WordApplication->Selection->set_Text(/*(WideString)Text*/ StringToOleStr("Текст"));

 Dim wrd As Object
 Dim bm As String
 bm = "mybookmark"
 wrd = CreateObject("Word.Application")
 wrd.Visible = True
 wrd.Documents.Open("D:\hlam\mydoc.doc")
 wrd.ActiveDocument.Bookmarks.Item(bm).Select()
 wrd.Selection.Text = "mytext!"

 Variant WordAppl;
 Variant Docs;
 Variant Doc;
 Variant BMs;
 Variant BM;
 Variant Range;

 WordAppl = Variant::CreateObject("Word.Application");
 WordAppl.OlePropertySet("Visible", Variant(true));
 Docs = WordAppl.OlePropertyGet("Documents");
	      Docs.Exec(Procedure("Open")<<ExtractFilePath(Application->ExeName)+"\\mydoc.doc");
 Doc=WordAppl.OlePropertyGet("ActiveDocument");
 BMs=Doc.OlePropertyGet("Bookmarks");

 BM=BMs.Exec(Procedure("Item")<<"MyBookmark"); // - не возвращает Variant поэтому ошибка в следующей строке
 BM.Exec(Procedure("Select"));

 Range=WordAppl.OlePropertyGet("Selection");
 Range.OlePropertySet("Text","MyText");