Retrieving child collection in a Transaction step

Hi,

I am trying to retrieve a child collection of a parent object in a java steplet of a transaction step. Example:

Customer object has a collection of order objects. A transaction has been defined for Customer object and order collection is also one of the transaction properties. I am able to access the customer object properties like name and id using transactionSession.getSessionData.getString('transaction.customerName'). How can I access the order collection in this case??

Thanks in advance

Amitoj Singh