Given the types of definitions present in most WSDL and XSD files, you must go down to the level of copying from or to a field within part of a variable based on the element and message type. This in turn uses XML schema complex types. To perform this action, you specify an XPath query in the from or to clause of the Copy Rules tab of the assign activity.

For more information about the Copy Rules tab, see Manipulating XML Data with bpelx Extensions and Assign Activity.