Hi Venkat,
Secondary data sources are not stored from one session to the next. These need to be queried each time they are needed.
If you need to preserve data, submit it as part of the xml, promote data into SharePoint columns, this data HAS to be a part of the main data source.
The workaround is to store the data in the main data source. Use rules to set the value of fields in the main data source.
Good luck!