Description:
------------
When encoding is set for both SoapClient and SoapServer (i.e.
ISO-8859-1) parameters are encoded properly to UTF-8 but not decoded on the other side.

Note: this error may be related to bug #38005 (SoapFault faultstring doesn't follow encoding rules) because before correction of this bug parameters were endoced/decoded properly, and now SoapFault parameters work fine but not method parameters.

Reproduce code:
---------------
[client]
<?php
$client = new SoapClient('a.wsdl'
		,array('encoding'	=> 'ISO-8859-1'));
$str = 'test: ?';
$res = $client->Test(array('str'=>$str));
?>

[server]
<?php
function Test($param) {
	file_put_contents('test.txt', $param->str);
	return 1;
}
$server = new SoapServer('a.wsdl'
		,array('encoding'	=> 'ISO-8859-1'));
$server->addFunction('Test');
$server->handle();
?>

[a.wsdl]
<?xml version="1.0" encoding="UTF-8"?>
<definitions
		xmlns:http="http://schemas.xmlsoap.org/wsdl/http/"
		xmlns:soap="http://schemas.xmlsoap.org/wsdl/soap/"
		xmlns:s="http://www.w3.org/2001/XMLSchema"
		xmlns:s0="http://test.pl"
		targetNamespace="http://test.pl"
		xmlns="http://schemas.xmlsoap.org/wsdl/"
>
	<types>
		<s:schema elementFormDefault="qualified"
targetNamespace="http://test.pl">
			<s:complexType name="Test">
				<s:attribute use="required" name="str" type="s:string"/>
			</s:complexType>
			<s:element type="s0:Test" name="Test"/>
			<s:element type="s:int" name="Ret"/>
		</s:schema>
	</types>

	<message name="TestSoapIn">
		<part name="parameters" element="s0:Test"/>
	</message>
	<message name="TestSoapOut">
		<part name="parameters" element="s0:Ret"/>
	</message>
	<portType name="TestSoap">
		<operation name="Test">
			<input message="s0:TestSoapIn"/>
			<output message="s0:TestSoapOut"/>
		</operation>
	</portType>
	<binding name="TestSoap" type="s0:TestSoap">
		<soap:binding transport="http://schemas.xmlsoap.org/soap/http"
style="document"/>
		<operation name="Test">
			<soap:operation soapAction="http:/Test/Test" style="document"/>
			<input>
				<soap:body use="literal"/>
			</input>
			<output>
				<soap:body use="literal"/>
			</output>
		</operation>
	</binding>
	<service name="Test">
		<port name="TestSoapPort" binding="s0:TestSoap">
			<soap:address location="http://localhost/server.php"/>
		</port>
	</service>
</definitions>

Expected result:
----------------
File text.txt shall contain exactly the same value as calling
parameter:

test: ?

Actual result:
--------------
Parameter isn't decoded from UTF-8:

test: &#258;?