In order to enable/disable Anti Virus Scanning for a particular domain from MailEnable one needs to perform below mentioned steps:
1) Login into MailEnable Professional.
2) Click on MailEnable -> MailEnable Management -> Messaging Center -> Post Offices.
3) Right Click on domain name -> Properties for which one need to perform the task.
4) Go to the Tab Feature Selection.
5) Check/uncheck the check box against Anti-Virus Scanning to Enable or Disable it.
6) Click on apply and Ok.