My experience with this says yes, you can use the same provider to write back. One gotcha to watch out for though. When I first started doing this, I was getting an error during the process of writing back to the 400 and our 400 people didn't know what was going on since I had all of the necessary rights. After scouring the Internet for days, I ran across a small hidden reference to the error I was getting. Turns out, in order to write back to the 400, they had to enable logging on that particular file before the security system would allow me to write. Once they set that up, all worked as expected.