In cart2details.xsl, line 83, we HTMLize the name of contents with this code:
<td><xsl:value-of select="@name"/></td>

I.e we display the name of contents, instead of their title.
We should instead use this:
<td><xsl:value-of select="metadata/title"/></td>

But it requires to change the CartElementsConcatenator._saxContents() so it SAXes the metadata/title of contents.