Attached Property in StateTriggers

The demo code like the follow below:

            <VisualState x:Name="view720">
                <VisualState.StateTriggers>
                    <AdaptiveTrigger MinWindowWidth="720" />
                </VisualState.StateTriggers>
                <VisualState.Setters>
                    <Setter Target="Text.(Grid.ColumnSpan)" Value="3" />
                    <Setter Target="Text.(RelativePanel.Below)" Value="Image" />
                </VisualState.Setters>
            </VisualState>

So just add the parentheses around the attached property and it would be worked fine on StateTriggers.