public function process( \Aimeos\MShop\Product\Item\Iface $product, array $data )
	{
		$manager = \Aimeos\MShop::create( $this->getContext(), 'product/property' );

		$propMap = [];
		$items = $product->getPropertyItems( null, false );
		$map = $this->getMappedChunk( $data, $this->getMapping() );

		foreach( $items as $item ) {
			$propMap[$item->getValue()][$item->getType()] = $item;
		}

		foreach( $map as $list )
		{
			if( ( $value = $this->getValue( $list, 'product.property.value' ) ) === null ) {
				continue;
			}

			if( ( $type = $this->getValue( $list, 'product.property.type' ) ) && !isset( $this->types[$type] ) )
			{
				$msg = sprintf( 'Invalid type "%1$s" (%2$s)', $type, 'product property' );
				throw new \Aimeos\Controller\Common\Exception( $msg );
			}

			if( isset( $propMap[$value][$type] ) )
			{
				$item = $propMap[$value][$type];
				unset( $items[$item->getId()] );
			}
			else
			{
				$item = $manager->createItem()->setType( $type );
			}

			$product->addPropertyItem( $item->fromArray( $list ) );
		}

		$product->deletePropertyItems( $items );

		return $this->getObject()->process( $product, $data );
	}