text: For a given document, each metadata type can have only one string associated with it. 
  
  So, for example, if the document has multiple keywords, they are passed to the add-in 
  
  as one concatenated string. 
  
  The*pwchValue*parameter specifies a Unicode string that contains the metadata itself. 
  
  How the add-in incorporates the text-string metadata into the exported document 
  
  depends on the implementation details of the export code and the type of fixed-format 
  
  used in the exported document. 