diff --git a/lib/v8/conversion/proc.rb b/lib/v8/conversion/proc.rb
index 64a5281..63a3ec2 100644
--- a/lib/v8/conversion/proc.rb
+++ b/lib/v8/conversion/proc.rb
@@ -9,27 +9,27 @@ class V8::Conversion
     end
 
     def to_v8_template
-      weakcell(:v8_template) do
-        template = V8::C::FunctionTemplate::New()
-        template.SetCallHandler(InvocationHandler.new, V8::C::External::New(self))
-        template
-      end
+      weakcell(:v8_template) {V8::C::FunctionTemplate::New(InvocationHandler.new(self))}
     end
 
     class InvocationHandler
       include V8::Error::Protect
+
+      def initialize(proc)
+        @proc = proc
+      end
+
       def call(arguments)
         protect do
           context = V8::Context.current
-          proc = arguments.Data().Value()
           length_of_given_args = arguments.Length()
-          args = ::Array.new(proc.arity < 0 ? length_of_given_args : proc.arity)
+          args = ::Array.new(@proc.arity < 0 ? length_of_given_args : @proc.arity)
           0.upto(args.length - 1) do |i|
             if i < length_of_given_args
               args[i] = context.to_ruby arguments[i]
             end
           end
-          context.to_v8 proc.call(*args)
+          context.to_v8 @proc.call(*args)
         end
       end
     end