Thanks for your reply. I found a way with custom atributes so i'm implementing it on this way now.

public class UmbracoRequired : RequiredAttribute, IClientValidatable
{
    public UmbracoRequired(string umbracoDictionaryKey)
    {
        this.ErrorMessage = Helpers.Dictionary.TranslatedLabel(null, umbracoDictionaryKey);
        this.ErrorMessageResourceName = null;
    }

    public IEnumerable<ModelClientValidationRule> GetClientValidationRules(ModelMetadata metadata, ControllerContext context)
    {
        yield return new ModelClientValidationRule()
        {
            ErrorMessage = this.ErrorMessage,
            ValidationType = "required"
        };
    }
}

Helpers.Dictionary.TranslatedLabel(null, umbracoDictionaryKey); is a function that gets the text from my umbraco dictionary.