[Zope] zserver and pdf's from buffer

I have PDF files stored in an Interbase database that I am retrieving with gvib from an external method. The result is a buffer object that I would like to output to the browser so that the acrobat control opens to display it. All I get though is the text of the pdf stream. I am setting the response content-type to application/pdf and I am using response.write() to stream the buffer out. Is this wrong? Do I need to create a temporary external file and send that instead? Thanks, Jason