ActiveAdmin: Nested attributes not working for STI

HI All,

I am having Model “Customer” using STI for sender and receiver, and i am
unable to save the both sender and receiver by nested attribute. Below are my model and active admin resource codes, correct me if i am wrong nested attribute on concept.

CUSTOMER MODEL:

class Customer < ActiveRecord::Base

belongs_to :sender, :class_name => "Customer"

has_many :receivers, :class_name => "Customer", :foreign_key => 'sender_id'

has_many :packages

accepts_nested_attributes_for :packages
accepts_nested_attributes_for :receivers

end

CUSTOMER ADMIN INTERFACE:

ActiveAdmin.register Customer do

form do |f|
 f.inputs "Sender Details" do

     f.input :name
 f.input :email

 f.input :street
 f.input :city

 f.input :state
 f.input :pin

  end

  f.inputs  do
f.has_many :receivers do |p|

 f.input :name
 f.input :email

 f.input :street
 f.input :city

 f.input :state
 f.input :pin

  end
end
f.inputs do #packages are saving correctly

 f.has_many :packages do |p|

  p.input :weight
  p.input :amount

  p.input :received_date
  p.input :amount

end
  end
  f.buttons
 end

end

regards,
Loganathan