Track purchase data with Google Analytics e-commerce without hard coding product information

Our company markets many products online and we need to track the purchase of each one through Google Analytics. In the e-commerce tracking examples I find the product info is hard coded in the tracking script.  Due to the nature of my product and the design of third-party sites hosting the e-commerce, I cannot hard code all the product info. I prefer to get the data as part of an array and pass those values back to Google Analytics.

Assuming the data fields have intuitive names (product, price, quantity, total), can you help me code the tracking script for that? Below is the example of what I do not want to do:

_gaq.push(['_addTrans',
      '1234',       // order ID
      'StoreName',  // store
      '19.99',      // total
      '1.50',       // tax
      '3.00',       // shipping
      'Tulsa',    // city
      'Oklahoma',   // state
      'USA'         // country
]);