diff --git a/lib/validates_timeliness/attribute_methods.rb b/lib/validates_timeliness/attribute_methods.rb
index 2ddc276..ba55343 100644
--- a/lib/validates_timeliness/attribute_methods.rb
+++ b/lib/validates_timeliness/attribute_methods.rb
@@ -22,9 +22,16 @@ module ValidatesTimeliness
             end
           EOV
           class_eval(method_body, __FILE__, line)
-        else
-          super
         end
+        super rescue(NoMethodError)
+      end
+
+    end
+
+    module InstanceMethods
+
+      def _timeliness_raw_value_for(attr_name)
+        @attributes_cache && @attributes_cache["_#{attr_name}_before_type_cast"]
       end
 
     end
@@ -35,7 +42,7 @@ module ValidatesTimeliness
         if timeliness_validated_attributes.include?(attr_name)
           method_body, line = <<-EOV, __LINE__ + 1
             def #{attr_name}_before_type_cast
-              @attributes_cache && @attributes_cache["_#{attr_name}_before_type_cast"]
+              _timeliness_raw_value_for('#{attr_name}')
             end
           EOV
           class_eval(method_body, __FILE__, line)
diff --git a/lib/validates_timeliness/validator.rb b/lib/validates_timeliness/validator.rb
index cd22ba6..2ad3478 100644
--- a/lib/validates_timeliness/validator.rb
+++ b/lib/validates_timeliness/validator.rb
@@ -56,8 +56,7 @@ module ValidatesTimeliness
     end
 
     def attribute_raw_value(record, attr_name)
-      before_type_cast = "#{attr_name}_before_type_cast"
-      record.send(before_type_cast) if record.respond_to?(before_type_cast)
+      record._timeliness_raw_value_for(attr_name)
     end
 
     def type_cast(value)
diff --git a/spec/validates_timeliness/attribute_methods_spec.rb b/spec/validates_timeliness/attribute_methods_spec.rb
index d2db27e..c778e25 100644
--- a/spec/validates_timeliness/attribute_methods_spec.rb
+++ b/spec/validates_timeliness/attribute_methods_spec.rb
@@ -4,19 +4,35 @@ describe ValidatesTimeliness::AttributeMethods do
   before do
     Employee.validates_datetime :birth_datetime
     Employee.define_attribute_methods
+    Person.validates_datetime :birth_datetime
+    Person.define_attribute_methods [:birth_datetime]
   end
 
-  it 'should define attribute write method for validated attributes' do
-    Employee.instance_methods(false).should include("birth_datetime=")
+  it 'should define _timeliness_raw_value_for instance method' do
+    Person.instance_methods.should include('_timeliness_raw_value_for')
+  end
+  
+  context "attribute write method" do
+    it 'should cache attribute raw value' do
+      r = Employee.new
+      r.birth_datetime = date_string = '2010-01-01'
+      r._timeliness_raw_value_for(:birth_datetime).should == date_string
+    end
   end
 
-  it 'should define attribute before_type_cast method for validated attributes' do
-    Employee.instance_methods(false).should include("birth_datetime_before_type_cast")
-  end
+  context "before_type_cast method" do
+    it 'should be defined on class if ORM supports it' do
+      Employee.instance_methods(false).should include("birth_datetime_before_type_cast")
+    end
 
-  it 'should store original raw value on attribute write' do
-    r = Employee.new
-    r.birth_datetime = '2010-01-01'
-    r.birth_datetime_before_type_cast.should == '2010-01-01'
+    it 'should not be defined if ORM does not support it' do
+      Person.instance_methods(false).should_not include("birth_datetime_before_type_cast")
+    end
+
+    it 'should return original value' do
+      r = Employee.new
+      r.birth_datetime = date_string = '2010-01-01'
+      r.birth_datetime_before_type_cast.should == date_string
+    end
   end
 end