Custom Page Size Crystal Report by Code

Dim oRpt As New CrystalDecisions.CrystalReports.Engine.ReportDocument
oRpt.Load(Server.MapPath("CrystalReport.rpt"))
oRpt.PrintOptions.PaperOrientation = [Shared].PaperOrientation.Portrait
oRpt.PrintOptions.PaperSize = [Shared].PaperSize.PaperEnvelope10

CrystalReportViewer1.ReportSource = oRpt