[xsl] How to iterate over all XML files in all subfolders in a folder?

["Costello, Roger L. costello@xxxxxxxxx" <xsl-list-service@xxxxxxxxxxxxxxxxxxxxxx>]

Hi Folks,

I have a folder that contains subfolders. Within each subfolder is a bunch of
XML files. I want to iterate over all the XML files in all the subfolders. I
tried the following and it doesn't work:

<xsl:for-each select="collection('folder/*?select=*.xml')">
    <xsl:message>
        Root element = <xsl:value-of select="name(/*)"/>
    </xsl:message>
</xsl:for-each>

What is the correct way to do this?

/Roger