use strict;
use XML::Rules;

my $parser = XML::Rules->new(
	stripspaces => 7,
	namespaces => {
		'http://www.w3.org/2005/10/markup-validator' => '',
		'http://www.w3.org/2003/05/soap-envelope' => 'env',
	},
	start_rules => {
		warnings => 'skip',
	},
	rules => {
		_default => 'content',
		error => 'as array no content',
		errorlist => 'no content',
		errors => sub { return errors => $_[1]->{errorlist}{error}},
		warning => sub {return warning => $_[1]->{message}},
		'markupvalidationresponse' => 'no content',
		'env:Body' => 'as is',
		'env:Envelope' => sub {return $_[1]->{'env:Body'}{markupvalidationresponse}},
	}
);

my $data = $parser->parse(\*DATA);
use Data::Dumper;

print Dumper($data);

__DATA__
<?xml version="1.0" encoding="UTF-8"?>
<env:Envelope xmlns:env="http://www.w3.org/2003/05/soap-envelope">
...