XML FeedItem propery publicationDate

Hi experts,

I'm trying to use a Feed Tile in my XML view but cannot figure how to fill the Feed Item property "publicationDate". Does anyone have any idea? Any input will be much appreciated.

<FeedTilexmlns="sap.suite.ui.commons"

       id="idfeedtile"

       displayDuration="5"

       displayArticleImage="true"

       source="Jaime"

       defaultImages=""

       press="">

             <tooltip></tooltip><!-- sap.ui.core.TooltipBase -->

             <dependents></dependents><!-- sap.ui.core.Control, since 1.19 -->

             <items><!-- sap.suite.ui.commons.FeedItem -->

                    <FeedItemxmlns="sap.suite.ui.commons"

                           id="iditem1"

                           title="Item 1"

                           image="http://miriadna.com/desctopwalls/images/max/Ideal-landscape.jpg"

                           link="www.google.com"

                           source=""

                           publicationDate="2012-01-23">

                    </FeedItem>        

             </items>

</FeedTile>

In debugger I can see exception Uncaught SyntaxError: Unexpected number

Many thanks in advance!

Jaime