diff --git a/lib/validates_timeliness/extensions/date_time_select.rb b/lib/validates_timeliness/extensions/date_time_select.rb
index 03ca7fd..5906593 100644
--- a/lib/validates_timeliness/extensions/date_time_select.rb
+++ b/lib/validates_timeliness/extensions/date_time_select.rb
@@ -14,8 +14,32 @@ module ValidatesTimeliness
 
       module InstanceMethods
 
-        TimelinessDateTime = Struct.new(:year, :month, :day, :hour, :min, :sec)
-
+        class TimelinessDateTime
+          
+          attr_accessor :year, :month, :day, :hour, :min, :sec
+          
+          def initialize(year, month, day, hour, min, sec)
+            @year  = year
+            @month = month
+            @day   = day
+            @hour  = hour
+            @min   = min
+            @sec   = sec
+          end
+          
+          # adapted from activesupport/lib/active_support/core_ext/date_time/calculations.rb, line 36 (3.0.7)
+          def change(options)
+            TimelinessDateTime.new(
+              options[:year]  || year,
+              options[:month] || month,
+              options[:day]   || day,
+              options[:hour]  || hour,
+              options[:min]   || (options[:hour] ? 0 : min),
+              options[:sec]   || ((options[:hour] || options[:min]) ? 0 : sec)
+            )
+          end        
+        end
+        
         def datetime_selector_with_timeliness(*args)
           @timeliness_date_or_time_tag = true
           datetime_selector_without_timeliness(*args)
@@ -32,7 +56,7 @@ module ValidatesTimeliness
           values = [nil] * 6
           pairs.map do |(param, value)|
             position = param.scan(/\(([0-9]*).*\)/).first.first
-            values[position.to_i-1] = value
+            values[position.to_i-1] = value.to_i
           end
 
           TimelinessDateTime.new(*values)
diff --git a/spec/validates_timeliness/extensions/date_time_select_spec.rb b/spec/validates_timeliness/extensions/date_time_select_spec.rb
index 2ac9796..298e156 100644
--- a/spec/validates_timeliness/extensions/date_time_select_spec.rb
+++ b/spec/validates_timeliness/extensions/date_time_select_spec.rb
@@ -101,6 +101,20 @@ describe ValidatesTimeliness::Extensions::DateTimeSelect do
       @output = date_select(:person, :birth_date, :include_blank => true, :include_seconds => true)
       should_not_have_datetime_selected(:birth_time, :year, :month, :day)
     end
+    
+    it "should support discarding of the day part" do
+      # this doesn't make sense for birthdays, but it does for credit card expirations, for example
+      @params["person"] = {
+        "birth_date(1i)" => 2009,
+        "birth_date(2i)" => 2,
+      }
+      person.birth_date = nil
+      @output = date_select(:person, :birth_date, :discard_day => true)
+      should_have_datetime_selected(:birth_date, :year => 2009, :month => 'February')
+      should_not_have_datetime_selected(:birth_date, :day)
+      @output.should have_tag("input[id=person_birth_date_3i][type=hidden][value='1']")
+    end
+
   end
 
   describe "time_select" do