The solution to this question is:
<?xml version="1.0" encoding="utf-8"?>
<?xml-stylesheet type="text/xsl" href="dummy.xsl"?>
<item>
<summary>
<![CDATA[Tootsie roll tiramisu macaroon wafer carrot cake. <br />
Danish topping sugar plum tart bonbon caramels cake.]]>
</summary>
</item>
by adding the <br />
inside the the <![CDATA]]>
this allows the line to break, thus creating a new line!