There are 2 problems with testByteArray and testByteArrayWrapper in MarshallRpcLitDIITestCase
1. The wsdl file used by the receiving end (the SEI) defines byteArrayTest incorrectly (not as intended by the test):
<message name="StandardTypes_byteArrayTest">
<part name="arrayOfbyte_1" type="xsd:base64Binary"/>
</message>

It should be:
<message name="StandardTypes_byteWrapperArrayTest">
<part name="arrayOfByte_1" type="ns5:ByteArray"/>
</message>

2. The schema generated by JavaToXSD for testByteArray and testByteArrayWrapper is incorrect :
It generates the following for both:

<complexType name='ByteArray'>
<sequence>
<element name='value' type='base64Binary' nillable='true' maxOccurs='unbounded' minOccurs='0'/>
</sequence>
</complexType>

It should be:

<complexType name='ByteArray'>
<sequence>
<element name='value' type='byte' nillable='true' maxOccurs='unbounded' minOccurs='0'/>
</sequence>
</complexType>