Printing on A5 paper problem

I'm trying to print
a fixedDocument on a A5 paper but I've a problem.

Some portion of the left side of the fixedDocument ommites and doesn't print.

I set the PageMediaSize of the PrintTicket to ISOA5 but it doesn't have any influence.

var dlg = new PrintDialog();
if (dlg.ShowDialog() == true)
{
  LocalPrintServer lps = new LocalPrintServer();
  PrintQueue pq = lps.DefaultPrintQueue;
  PrintTicket pt = pq.DefaultPrintTicket;
  pt.PageMediaSize = new PageMediaSize(PageMediaSizeName.ISOA5);
  dlg.PrintDocument(fixedDocument.DocumentPaginator, "Menu Plan");
} 

Is there any idea?

Amir