Description of problem:

Cannot create an option with mode "set" for an Apache virtual host.

How reproducible:

Always

Steps to Reproduce:
1. Edit an existing virtual host configuration
2. Click "Add New" to add a new Option
3. Leave the Mode as "Set", select any type of "Option"
4. Try to save the form
5. Observe the error message stating that "For property "Mode", a value is required."
  
Actual results:

Cannot create an option in the "Set" mode.

Expected results:

The above should be possible.

Additional info:

This is most probably caused by the value of the modes. "Set" is modelled as an empty string in the RHQ configuration (because it is modelled like that in the httpd.conf), which confuses the form validation.