you can add 'logFormat' node to every task configuration.
like this example:
Code:
<task>
<logFormat>ARCHIVE: "Archive" "Moving {0} from {1} to {2}"</logFormat>
<status>Enabled</status>
<actionType>Move</actionType>
<source>E:\\temp\\TestFiles</source>
<sourceVirtual>/temp/TestFiles/</sourceVirtual>
<destination>E:\\temp\\archive</destination>
<destinationVirtual>/archive/</destinationVirtual>
<action id="TotalFolderUsedSpace">
<value>12345000</value>
<minFolderAction>2</minFolderAction>
</action>
</task>
this would write something like this into ioFTPD.log
datetime ARCHIVE: "Archive" "Moving blabla from asda to ttt"