public virtual Band CreateInstance(
    BandKind bandKind
)

Public Overridable Function CreateInstance(
    bandKind As BandKind
) As Band

using DevExpress.XtraReports.UI;
// ...

public class MyCustomPageHeaderBand : PageHeaderBand {
    public string MyCustomBandProperty { get; set; }
}

public class MyCustomBandFactory : BandFactory {
    public override Band CreateInstance(BandKind bandKind) {
        if (bandKind == BandKind.PageHeader)
            return new MyCustomPageHeaderBand();
        return base.CreateInstance(bandKind);
    }
}

Imports DevExpress.XtraReports.UI
' ...

Public Class MyCustomPageHeaderBand
    Inherits PageHeaderBand
    Public Property MyCustomBandProperty() As String
        Get
            Return m_MyCustomBandProperty
        End Get
        Set
            m_MyCustomBandProperty = Value
        End Set
    End Property
    Private m_MyCustomBandProperty As String
End Class

Public Class MyCustomBandFactory
    Inherits BandFactory
    Public Overrides Function CreateInstance(MyBandKind As BandKind) As Band
        If MyBandKind = BandKind.PageHeader Then
            Return New MyCustomPageHeaderBand()
        End If
        Return MyBase.CreateInstance(MyBandKind)
    End Function
End Class

using DevExpress.XtraReports.UI;
// ...

public class XtraReport1 : XtraReport {
    public XtraReport1() {
        InitializeComponent();
        bandFactory = new MyCustomBandFactory();
    }
}

Imports DevExpress.XtraReports.UI
' ...

Public Class XtraReport1
    Inherits XtraReport

    Public Sub New()
        InitializeComponent()
        bandFactory = New MyCustomBandFactory()
    End Sub
End Class