Copy Record - Obtain Internal ID of Copy From

Upon clicking Make Copy (of a custom record) I need to generate some script to also copy certain "child" records.

How do I access the Internal ID of the Copy From record?

Do I access it in BeforeLoad using a User Event Script (tried that but got error = Error: SSS_MISSING_REQD_ARGUMENT
id
Stack Trace: cloneForm(ss_cloneequip1.js:8)
) ? 

if (type == 'copy')
   {
      var newEquipRecord = nlapiGetNewRecord();
      var stEquipID = nlapiGetRecordId();
      var arrEqInfo = new Array();
      arrEqInfo['custparam_equipid'] = stEquipID;
      nlapiSetRedirectURL('SUITELET','customscript_ss_cloneequip1','customdeploy_ss_cloneequip1', null,arrEqInfo);
    }

Or access via Page Init function using a Client Side Script?  If I need to use this I assume the Page Init is fired for the new record and therefore how do I find the internal id for the copied from record?