Как заменить значение переменных для текста MS Word?

uses
  Office97; {or Office2000, OfficeXP, Office_TLB}

var
  VDoc, PropName, DocName: OleVariant;
  VDoc := Word.ActiveDocument;
  { ... }

{ Set a document property }
PropName := 'MyOpinionOfThisDocument';
VDoc.CustomDocumentProperties.Add(PropName, False, msoPropertyTypeString,
  'Utter drivel', EmptyParam);
{ Read a document property }
Caption := VDoc.CustomDocumentProperties[PropName].Value;
{ ... }