Hmmm. Okay, maybe I shouldn't have asked a bunch of VB developers!
Lol there are a few of us here who do C# but EWS and exchange integration are fairly specialist, either you have done it or you haven't!

I've written an application that will read the emails in a given mailbox and save the attachments. Unfortunately, I've now been told that they will have to be saved to a network location on another domain.
I think my only option is to save it locally on my current domain and then use impersonation (another new thing for me!) to copy it over. Does that sound sensible?
Why do you need to use Impersonation? if you save the attachments locally to you, can you not just copy them across as files to the other domain location? OR am i missing part of your requirement?