Custom Verifier Attribute?

//The NullEntityVerifier

    public class NullEntityVerifier : PropertyValueVerifier {
      public NullEntityVerifier(Type entityType, String propertyName,
        String displayName = null, bool? shouldTreatEmptyStringAsNull = null)
        : base(new PropertyValueVerifierArgs(entityType, propertyName, false,
          displayName, shouldTreatEmptyStringAsNull)) {
      }

      public NullEntityVerifier(PropertyValueVerifierArgs args) : base(args) { }

      protected override VerifierResult VerifyValue(object itemToVerify, object valueToVerify, 
        TriggerContext triggerContext, VerifierContext verifierContext) {

        var entity = (Entity)valueToVerify;
        var result = !entity.EntityAspect.IsNullEntity;
        return new VerifierResult(result);
      }
    }

//The NullEntityVerifierAttribute

    [AttributeUsage(AttributeTargets.Property | AttributeTargets.Field, Inherited = false)]
    public class NullEntityVerifierAttribute : PropertyValueVerifierAttribute {
      protected override Verifier BuildVerifierCore(Type pType, String propertyName) {
        return new NullEntityVerifier(
          new PropertyValueVerifierArgs(pType, propertyName, false, DisplayName, 
            GetShouldTreatEmptyStringAsNull())
          );
      }
    }

//The buddy class

    public class EmployeeMetadata {

      [NullEntityVerifier]
      public static Employee Manager;
    }

//The generated code

    #region Manager property

    /// <summary>Gets or sets the Manager. </summary>
    [DomainModel.Employee.NullEntityVerifier]
    [Bindable(false)]
    [Display(Name="Manager", AutoGenerateField=false)]
    [DataMember]
    [IbEm.RelationProperty("FK_Employee_Employee", IbEm.QueryDirection.ToRole2)]
    public Employee Manager {
      get { return PropertyMetadata.Manager.GetValue(this); }
      set { PropertyMetadata.Manager.SetValue(this, value); }
    }
    #endregion Manager property