The ability to perform custom time window data load and warehouse data deletion from the command line has been introduced in Strategy Enterprise Manager 8.0.2 Hotfix 1. The MAEMETL command can be executed with the 'CWM' switch for the custom time window data load and 'WHD' switch for the warehouse data deletion.
See the image below of the Strategy Enterprise Manager Data Migration help dialog box, which provides the syntax and a description of the tasks performed by the various switches, including the new ones:

To perform a custom time window data load for the data logged between the dates 04/10/2006 to 04/11/2006, use the following expression:
MAEMETL -CWM -04/10/2006 -04/11/2006

For related information regarding the other switches listed in the image above, refer to the following Strategy Knowledge Base technical note:
TN Key: 8087 - How to trigger the Enterprise Manager Data Load process from the command line in Strategy Administrator - Enterprise Manager