or
// in ctor of main report
sr1099Top.ReportSource = new Forms.v5.SR_Vendor1099() { Name = "sr1099Top" };
sr1099Bottom.ReportSource = new Forms.v5.SR_Vendor1099() { Name = "sr1099Bottom" };
sr1099Top.ReportSource.DataSource = sr1099Bottom.ReportSource.DataSource = ds.Tables["Vendors"].DefaultView;