Philipp Kursawe schrieb:

thanks Michael! Is there a way to format the tags to lowercase when
they are attributes?

Yes:

    <xsl:attribute name="{
      translate( name(),
        'ABCDEFGHIJKLMNOPQRSTUVWXYZ',
        'abcdefghijklmnopqrstuvwxyz' ) }">

The above is for XSLT version 1.0. Note that in 2.0, there is a much
bigger and better function library than in 1.0.

If you have to use 1.0, there is EXSLT. If that's not enough, there is
an escape to calling the XSL transform from Perl, PHP, or whatever, and
make the host language functions available to the XSL transform.