I am trying to change the background style of the CalendarDay when IsSelected="True" by using a trigger like this:

<Style BasedOn="{StaticResource CalendarDayBase}" TargetType="igPrim:CalendarDay">
<Setter Property="Background" Value="#FFFFC5" />
<Style.Triggers>
<Trigger Property="IsSelected" Value="True">
<Setter Property="Background" Value="Red" />
<Setter Property="BorderBrush" Value="Red" />
<Setter Property="BorderThickness" Value="8" />
<Setter Property="Foreground" Value="Red" />
<Setter Property="FontWeight" Value="Bold" />
</Trigger>
</Style.Triggers>
</Style>

The borderthickness gets set, but none of the other properties get set.

I am also re-styling the XamCalendar template, but I have kept the Calendar Day properties the same: 

<Style x:Key="CalendarDayBase"
BasedOn="{StaticResource CalendarItemBase}"
TargetType="igPrim:CalendarDay" />
<Style BasedOn="{StaticResource CalendarDayBase}" TargetType="igPrim:CalendarDay" />

Thanks in advance for any help!