Hi Rafael,
Currently you can only create custom editor template in which you can add the standard validation rules to the editors or extend the build-in validator to add your custom validation rules. For convenience I created small example of extending the build-in validation rules to include custom validation for the "description" field:
Kind Regards,
Vladimir Iliev
Telerik
Join us on our journey to create the world's most complete HTML 5 UI Framework -
download Kendo UI now!