That's by default. Any string property is mapped to "Ansi" (varchar) in database. I believe your database was not created by Aurelius, but instead was already created with types "NVarchar" instead of "Varchar"?
IF that's the case, all you have to do is change a global configuration:
uses Aurelius.Global.Config;
TGlobalConfigs.GetInstance.MapStringToNationalChar := true;