my $xml_obj = new XML::Smart( $xml ) ;
my $hash_when_cat_eq_special = ( $xml_obj->{list}{value}( 'category', 'eq', 'special' )->pointer() );

##</code><code>##

$hash_when_cat_eq_special will contain:
{
  "/nodes"    => { parameter => 1 },
  "/order"    => ["category", "parameter"],
  "category"  => "special",
  "parameter" => {
                   "/order"   => ["instance", "CONTENT"],
                   "CONTENT"  => "\n              nameofparameter1\n          ",
                   "instance" => 0,
                 },
}

##</code><code>##

my $xml_obj = new XML::Smart( $xml ) ;
my $param_contents = $xml_obj->{list}{value}( 'category', 'eq', 'special' )->{parameter}->content();

##</code><code>##

$param_contents will contain: 
"nameofparameter1"