For whatever reason, I still find this to be a confusing answer.
Like I said, I currently have GA capturing data, and I used goals to measure conversions with thank you page hits. Is this what you said in your first paragraph? I am already doing this with no problems.
Does your second paragraph say the following?
WARNING!! IF YOU ARE USING A COMMON THANK YOU PAGE, IT IS IMPOSSIBLE FOR GA TO COLLECT ECOMMERCE TRACKING DETAILS!!
Am I reading what you wrote incorrectly? Or, is there a way to add a code snippet that sends the information to GA? I really would like to keep the common thank you page, but also have GA collect ecommerce tracking details. Please tell me how to do this.