Mule soft data transformation/mapper in anypoint studio

My process requires to schedule a job that invokes a web service operation to receive data, transform/map it to an XML and FTP it. I get lots of fields from the web service operation call that I will invoke, in one of the field we will receive a string which contains multiple lines of data. I need to map each line to a field in xml (array list in XML).The rest of the fields from web service call to XML are one to one mapping. Can I achieve this in data mapper? If so, can you please guide me. I can retrieve the string variable (from web service call) using Xpath and use Java sub string to retrieve data in each line and store it in an array. How do I call this array and map from this array in data mapper along with the other fields that I retrieve from web service call. Please let me know if you need any more details. Thanks in Advance.