Ada 2005 problem using Iterate

[Roger <rogermc@grapevine.com.au>]

I've successfully used Iterate quite often before but the attached code won't work and I can't figure out why.
Presumably something obvious that I'm blind to!
No matter what I try, compiling numbers.adb produces the error messages:

numbers.adb:24:48: expected access to subprogram "Ada.Containers.Vectors." from instance at numbers.ads:17
numbers.adb:24:48: found type access to procedure "Show_Two_Numbers" defined at line 24

numbers.ads:17 is:
     package pNumbers_Vector is new  Ada.Containers.Vectors (tNumbers_Index, tNumbers);
numbers.adb:24 is:
     Numbers_Vector.Iterate(Show_Two_Numbers'Access);

Can someone tell me what I'm doing wrong?
Regards,
Roger

Numbers.ads:
with Ada.Containers.Vectors;
package Numbers is
    type tNumbers_Vector is private;
    procedure Print_Numbers_Data  (Numbers_Vector : tNumbers_Vector);
private
   type tNumbers is record
      n1                    : Integer := 0;
      n2                    : Integer := 0;
   end record;

 subtype tNumbers_Index is Natural;
 package pNumbers_Vector is new  Ada.Containers.Vectors (tNumbers_Index, tNumbers);
 type tNumbers_Vector is new pNumbers_Vector.Vector with null record;
end Numbers;

============================================================

Numbers.adb:
with Ada.Text_IO; use Ada.Text_IO;

package body Numbers is
    Numbers_List : tNumbers_Vector;
    function  New_Record(n1 : Integer; n2 : Integer) return tnumbers is
        theRecord : tnumbers := (n1, n2);
    begin
        return theRecord;
    end New_Record;

    --  ----------------------------------------------------------------------------------------------------

    procedure Print_Numbers_Data  (Numbers_Vector : tNumbers_Vector) is

        procedure Show_Two_Numbers(Number_Index : tNumbers_Index) is
             aNumber_Record    : tnumbers;
        begin
             aNumber_Record := Numbers_Vector.Element(Number_Index);
             Put("Number 1: " & Integer'image(aNumber_Record.n1));
             Put_Line("      Number 2: " & Integer'image(aNumber_Record.n2));
         end Show_Two_Numbers;

  begin
        Numbers_Vector.Iterate(Show_Two_Numbers'Access);
  end Print_Numbers_Data;

    --  ----------------------------------------------------------------------------------------------------

begin
    for index in Natural range 0..3 loop
        Numbers_List.Append(New_Record(index + 2, 2* index + 1));
    end loop;
end Numbers;