Resolution:
When accessing a Service via SOAP by using a generated proxy, an exception similar to the following may occur on Engines:

org.xml.sax.SAXException: Deserializing parameter 'data': could not find deserializer for type {java.client.dealvaluator.examples}MarketData
at org.apache.axis.message.RPCHandler.onStartChild(RPCHandler.java:302)
...

When the targetPackage name is not set in the Service Type Registry page and a generated proxy is used, deserialization errors will occur. To remedy this, edit the Service Type on the Service Type Registry page of the GridServer Administration Tool and assign a value for the targetPackage property.