replace

					<xsl:value-of select="Frage"/>
					

by

<xsl:apply-templates select="Frage"/>

then just have templates matching elements (not tags0 that you want to
transform.

You want to transform Fixed to nothing so add

<xsl:template match="Fixed"/>

(You could probably simplify the rest of your stylesheet by using
matching templates rather than named templates as well)

David