Save FM Book as PDF: Set ElementBoundaryDisplay

I am working on a script to save multiple framemaker book files as PDFs.  The books successfully save to PDF, but the element boundaries are displayed as tags in the pdf.

I have tired both:

app.ActiveDoc.ElementBoundaryDisplay = 0

and

app.ActiveBook.ElementBoundaryDisplay = 0

while the book is open in Framemaker.  Neither work.

This is my PDF saving function:

function saveToPDF(fileObject, savePath) {      var saveParams, i;     saveParams= GetSaveDefaultParams();          i = GetPropIndex(saveParams, Constants.FS_FileType);      saveParams[i].propVal.ival = Constants.FV_SaveFmtPdf;        var saveAsName = savePath;      var returnParamsp = new PropVals();      fileObject.Save(saveAsName, saveParams, returnParamsp);  
}  

Any ideas on how to make sure element boundary display is turned off in an active book?