When a field is set to read-only with setFieldViewMode, the $aData array in the OnCorrect function contains the field as array key with an empty value.
When setFieldViewMode is used, there is no POST for this field. Therefor the data array should not contain the array key.
exactly what I want it to be. The field is in viewmode, the user can not change it, but is should be posted. If there is no value, the field is still in the form, just not to be altered by the user