Integrating Fedex into your web application

I realize they have an API but some of the questions I have wouldn't be answered by it, and it would be great to receive feedback from others who have integrated it before.

I basically am working with a web site where visitors may choose to sell a used item to the site owner.

If the user decides to sell, he can enter in the specifications of the item and be given a quote. Then he'll proceed to enter in his address, which I assume I'll have to verify using the Fedex API before or during the part where it creates a shipping label.

So assuming the address is verified, it looks like the script in the API I have to interact with is /Ship/Ground/Domestic/ShipGroundDomestic.php5 ( since we will not integrate any other type of shipment type yet ).

Is this is the script that actually creates the shipment and charges the account setup, assuming all goes well it returns a xml response with the status?
Since it's SOAP based - I realize there are options for a pdf and png shipping label type, it looks like it generates the label but where is it actually stored, is it just temporary?
In the script it specifies options for a API Key, password, account #, and Meter # - so I would have to actually know the site owners credentials, since it charges for creating shipments/labels I can't use a normal account that doesn't have a CC setup, can I?
I can't actually test anything without contacting them and telling them to make my account go into test mode? Or is there an extra parameter for test mode?
I should store all shipments in a local database to pull them up, right? Or should I solely rely on Fedex for storing all the information? If I use a local database I can map shipments to users and use a Fedex provided script to look up the delivery status so I would think I have to do that.
If I were to have a feature that automatically emailed customers with status updates of a delivery, I would have to use some type of cron job to look and see if there were any updates made, I can't do this any other way?

Solution

If you are using the the Fedex Web Services API you get a test key by going to https://www.fedex.com/wpor/wpor/editConsult.do (You may need to be already signed in).

The label it generates it just dumps into the current directory. That is obviously not acceptable for production code, since it does not even generate a unique file name, but the php file is example code. Modify the code they give to do whatever you want with the returned label.

You would want a local database.

Why would you want to send users updates? Is there any reason they cannot just use the tracking number and look it up themselves? I mean it would be possible to call the tracking API periodically and generate emails, but do users really want these emails?