t.apache.org/dtds.data/wicket-xhtml1.3-strict.dtd is added to the root element to allow the XSL processor to handle the wicket namespace.
The reason why the transformer can not be used to XSLT the ListViews output is because of the ListViews markup being reused for each ListItem. Please use a XsltOutputTransformerContainer instead. Note: if the ListView is used to print a list of <tr> tags, than the transformer container must enclose the <table> tag as well to be HTML compliant.
@see org.apache.wicket.markup.transformer.AbstractOutputTransformerContainer
@see org.apache.wicket.markup.transformer.XsltOutputTransformerContainer
@author Juergen Donnerstag