Hi,
Please check below steps helpful for your requirement by creating two flows and additional files.
Interface1: This interface to read the filenames from done*.xml and generate the additional files with same name with different extension like xxx11092014.txt and zzz10092014.txt for interface2 to pick.
1. Configure your sender CC to pick file done*.xml
2. Use multimapping to create multiple messages based on how many files under <files>
3. Create additional files in receiver file adapter with same name with different extension by using variable substitution.
Interface2: This interface to pick files having only additional files with same namepart
1. Configure your sender CC to pick files having additional files by enabling Additional Files
Regards,
Praveen