Yves,
I'm not an authority on this, but I do know from my web development experience that the shift away from FTP has been happening for quite some time now that there's a lot of nice support for file uploads over HTTP, be it through the standard file upload control, or a Flash or Silverlight application.
It might be worth the investment of time to get an HTTP upload solution on your server, whether just a simple app or a web service...
Sorry, this probably isn't the answer you were looking for
.
Cheers,
-Jeff
Jeff Wilcox [MSFT]
Developer
Silverlight Toolkit
http://www.jeff.wilcox.name/blog/
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