correlation set BPEL

Part1

structure>>correlationsets>>process>>correlationsets>>green plus icon >>set any name(Say EmployeeIdentifierSet)>>add new property>>name(say EmployeeIdentifier)>>type chooser icon and select string as the property type >>OK

PART2

The value of a property is associated with the content of the messages sent to or from the process at such exchange moments. 
These associations etween the property and a particular message exchange are specified using property alias definitions 
Structure>>node Property Aliases >>Click on the green plus icon to create a new property alias >>Accept the default interaction type of Message Type >>Open the node Message Types and the child node Partner Links. Find and expand the node for partner link from where  this value is coming>>Select the payload node>>Type / (forward slash) in the Query field. A selection of available element names is presented >>choose  and press\. again till u reach your element

PART3

We need to specify now that the Reply activity instantiates the correlation set: 
Open the activity editor by double clicking the Reply activity>> Go to the Correlations tab>>Click the green plus icon to add a correlation set that is associated with this message exchange. >>select the correlation set u wanna use>>You need to set Initiate to yes to indicate that this Reply step is the moment when this correlation set is instantiated and the identifier for this process instance is fixated 

PART4