APEX

I am on APEX 4.2 and have a bar chart with 2 series. The series are 'Last Week' and 'This Week'. I am trying to display custom items values int he legend next to the appropriate series. I put in the following code, but its not showing the legend at all (just a little square where the default legend used to be). What am I missing?

        <legend enabled="true" ignore_auto_item="True" position="Top" align="Near" elements_layout="Vertical">

          <title enabled="False"/>

        <items>

          <item source="Series" series="Last Week">

            <format><![CDATA[{%Icon} Last Week - &P13_21_AVG_LAST_WEEK.]]></format>

          </item>

          <item source="Series" series="This Week">

           <format><![CDATA[{%Icon} This Week - &P12_21_AVG_THIS_WEEK.]]></format>

          </item>

         </items>

          <font family="Tahoma" size="10" color="0x000000" />

        </legend>