Segoe UI Light vs FontWeight="Light"

Question

Hello,

Why does the following two styles not apply the same style in Silverlight 5? It seams like it is ignoring the FontFamily property.

Thanks

Henrik

        <Style x:Key="PageHeaderTextStyle1" TargetType="TextBlock">
            <Setter Property="Foreground" Value="Black"/>
            <Setter Property="FontFamily" Value="Segoe UI Light"/>
            <Setter Property="FontSize" Value="56"/>
        </Style>

        <Style x:Key="PageHeaderTextStyle2" TargetType="TextBlock">
            <Setter Property="Foreground" Value="Black"/>
            <Setter Property="FontFamily" Value="Segoe UI"/>
            <Setter Property="FontSize" Value="56"/>
            <Setter Property="FontWeight" Value="Light"/>
        </Style>