would like to align two gridviews horizontally

pdfTable = New PdfPTable(1)
          Phrase = New Phrase()
          pdfTable.DefaultCell.Padding = 5
          pdfTable.WidthPercentage = 50
          pdfTable.HorizontalAlignment = Element.ALIGN_RIGHT
          pdfTable.DefaultCell.BorderWidth = 1
          pdfTable.SpacingBefore = 15.0F
          cell = New PdfPCell(New Phrase("For Post office use only"))
          cell.BackgroundColor = New iTextSharp.text.Color(240, 240, 240)
          cell.Padding = 5
          pdfTable.AddCell(cell)
          For x As Integer = 1 To 5
              cell = New PdfPCell(New Phrase(""))
          Next
          pdfDoc.Add(pdfTable)
          pdfTable = New PdfPTable(2)
          Phrase = New Phrase()
          pdfTable.DefaultCell.Padding = 3
          pdfTable.WidthPercentage = 20
          pdfTable.HorizontalAlignment = Element.ALIGN_Left

          pdfTable.DefaultCell.BorderWidth = 1
          pdfTable.SpacingBefore = 15.0F
          Dim _Contact As New ArrayList
          _Contact.Add("Date of Posting")
          _Contact.Add("Company Name")
          _Contact.Add("Customer Name")
          _Contact.Add("Telephone Name")
          _Contact.Add("Customer Signature")
          For x As Integer = 0 To _Header.Count - 1
              pdfTable.AddCell(_Contact(x).ToString)
              pdfTable.AddCell("")
          Next
          pdfDoc.Add(pdfTable)