Modify return data from related field

Hi,

I'm working on Sugar 7.5 Enterprise, i have a relation between accounts and oportunitties and i need to copy a content field from the accounts module and paste into a field in the opportunitties module, but keeping this field editable.

In SugarCE 6.5, i can modify the open_popup function in the related field from the opportunities module and add the required field:

open_popup(
  "Accounts", 
  600, 
  400, 
  "", 
  true, 
  false, 
  {"call_back_function":"set_return","form_name":"EditView","field_to_name_array":{"id":"account_id","name":"account_name", "my_account_field":"my_opportunity_field" }}, 
  "single", 
  true
);

But in Sugar 7.5 this process it's very different, i extends a record.js in the opportunities module, but i don't know how to modify the related field functionality.

Thanks for the help.