In the SOAP envelopes I showed data type encoding. hello world!]]> SOAP provides 16 basic data types, and 28 derived data types through the use of XML Schema. PHP obviously does not have that many data types, so many SOAP types are mapped into PHP types, somewhat arbitrarily. array( 'string' => 'string', 'boolean' => 'boolean', 'float' => FLOAT, 'double' => FLOAT, 'decimal' => FLOAT, 'duration' => 'integer', 'dateTime' => 'string', 'time' => 'string', 'date' => 'string', 'gYearMonth' => 'integer', 'gYear' => 'integer', 'gMonthDay' => 'integer', 'gDay' => 'integer', 'gMonth' => 'integer', 'hexBinary' => 'string', 'base64Binary' => 'string', // derived datatypes 'normalizedString' => 'string', 'token' => 'string', 'language' => 'string', 'NMTOKEN' => 'string', 'NMTOKENS' => 'string', 'Name' => 'string', 'NCName' => 'string', 'ID' => 'string', 'IDREF' => 'string', 'IDREFS' => 'string', 'ENTITY' => 'string', 'ENTITIES' => 'string', 'integer' => 'integer', 'nonPositiveInteger' => 'integer', 'negativeInteger' => 'integer', 'long' => 'integer', 'int' => 'integer', 'short' => 'integer', 'byte' => 'string', 'nonNegativeInteger' => 'integer', 'unsignedLong' => 'integer', 'unsignedInt' => 'integer', 'unsignedShort' => 'integer', 'unsignedByte' => 'integer', 'positiveInteger' => 'integer', 'anyType' => 'string', 'anyURI' => 'string', 'QName' => 'string' ) ]]>