Yes you can put in values in to the simulator that you think 2CO will return in a Live transaction and get your scripts to function on what YOU ASSUME will be correct. BUT you won’t know for sure until you run live transactions and then that’s where your problems are going to start.

From this point you’re going to have to deal with 2CO tech support which in my opinion they aren’t interested in you developing a 3rd party cart and are VERY SLOW in answering questions.

It appears that right now we’d have to manually fill in all the fields (or use your defaults for a sample order, “creating” that order first). Here’s an idea: besides the existing functionality, also offer the simulator from within the vendor area – to simulate refunds, etc. of real orders that already exist in the system. This would save the “copy & paste effort” and would likely result in more reliable testing before the functionality is turned on (by the vendor) for very similar orders for real.