Refer LISA SDK: Filter to save Result Set in an Excel Sheet for Set Up Instructions.
3. Provide values for highlighted field:
It will save the XML Response to the property provided for parameter: Property Name.
This property can further be an input to any step or can be saved to file using Filter "Save Property value to File".
Note: This Filter might be available in latest versions. I have created it for DevTest 8.4 or less than that.