Maybe I wasn't as clear as I should have been in the original post.
There is nothing wrong with Twain scanning or "more correctly TWAIN scanning". This prospect MUST USE TWAIN SCANNING.
It is not going to be sent to anyone, so it doesn't need to me an attachment or go into a folder.
It will go into an application. They will click on something in the application (such as aquire image) and the program will pull from the mfp feeder in real time.
The 1515 does have a USB port. However, my experience has been that scanning can only be done through 10/100 Base TX, IEEE 802.11b Wireless LAN, or IEEE 1394. Scanning through USB is not supported.
When the 1515 is installed on the network with 10/100 Base TX (standard cat5 cable), the scan driver looks out over the network and finds the scanner and pulls from it.
Now, the only obstacle is whether or not Remote Desktop Connection will allow this to be done through the VPN.