Hi, I see your project and it is quite interesting. In fact, I have developed a couple of projects like the one you are asking for, so surely I can help you with this one. I am an IT engineer and I work exclusively with Outlook projects, if you check my profile you'll see that most of my projects are Outlook projects.
In your project, you should consider the use of the EML format to save your emails. This is the standard format to export emails on external disk, including its attachments. Once you get the email in EML format, you can save it into a folder, to an external disk or upload it to your server. And using an Outlook Add-In is the best place to put all these functionality, the routines to create the EML files and the routine to upload the EML file to your server.
I already have code that perform all these tasks, so if you allow me, I can send you some screenshots of these plugins so you can have a glance of how they look like. I can also code the server side of your project, if you still don't have it. The code in the server is the one responsible to handle and manage all the EML files you upload using the Add-In.
This Add-In would also work for Outlook-2010-2013 or 2007 if you need so. Using an Installshield installer, where the user only has to click next, next, next and open Outlook. Very simple and straightforward.
Well, I think that is all by now. If you have any question, just send a message.
Regards.
Joe.