$propParam1->PropertyName = "Date";
		$propParam1->PropertyMatchString = "17/05/2011";
		$propParam2->PropertyName = "Series";
		$propParam2->PropertyMatchString = "2";

		$findContentParams->SessionContext = $sessionContext;
		$findContentParams->ServiceID = "419";
		$findContentParams->MaxResult = "24";
		$findContentParams->StartPos = "0";
		$findContentParams->SearchString = $searchString;
		$findContentParams->SortOption= $sortOption;
		$findContentParams->PropertiesFilterParameters = array ( $propParam1, $propParam2 );
		$findContentParams->PropertiesFilter ="%1 && %2";

		$client = new SoapClient( "http://cs2.acme.com/ContentService.svc?wsdl", array( 'location' => "http://cs2.acme.com/ContentService.svc/basic" ) );

		$findContentResponse = $client->FindContent( array( 'parameters' => $findContentParams ) );

Code snippet showing how to use FindContent for properties using advanced properties filter (i.e. with special characters)

PHP Advanced PropertiesFilterParameters

PHP