We have received a new build from n-software which included some enhancements related to the FTP context properties. I previously explained how any properties that were set via code would override any of the configured properties in the static send port. To see the original post check it here: http://kentweare.blogspot.com/2007/06/n-software-ftp-adapter.html
As of build 2.1.2729, you can still set these properties in your code. The difference now is that you can specify these properties as macros in your send port configuration(inside of BizTalk Admin).
So if you populate the msgOut(nsoftware.BizTalk.FTP.User) property in your code, you would now configure the static send port and specify the user as %User%.
You would follow the same pattern for any other context properties that you populate inside of your code such as msgOut(nsoftware.BizTalk.FTP.FTPServer) . In this case the macro in BizTalk Admin would be %FTPServer%.