Authorize.net update_profile not updating the merchant customer ID Rails 3

I am using Rails 3.2.12 and ruby 1.9.2

I need to update the email in authorize.net when the user changes the email in user profile edit page.

I tried the following update_profile method

transaction = AuthorizeNet::CIM::Transaction.new(AUTHORIZE_NET_API_LOGIN_ID,AUTHORIZE_NET_TRANSACTION_KEY,:gateway => :"#{AUTHORIZE_NET_GATEWAY}")
response = transaction.update_profile({:email => "test@gmail.com", :description => "#{HOSTNAME}", :merchant_customer_id => "155", :customer_profile_id => @user.profile_id})

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The response from the authorize.net is success. But the merchant_customer_id 155 not updating in authorize.net server.

I tried using it as :id, :customer_id for the merchant customer id, but nothing updating the details.

Anyone know about to pass the parameters correctly to update the authorize.net profile. please help me.

Thank you.