I thought MVC was supposed to make all this easier but I'm trying various ways and getting issues.
If I try the accepted answer for this question (changing the content type accordingly)... http://stackoverflow.com/questions/1375486/how-to-create-file-and-return-it-via-fileresult-in-asp-net-mvc
...I get into trouble because my encoding in the xml file is UTF-16.
The error I get is:
Switch from current encoding to specified encoding not supported.
This suggests that somewhere I need to tell MVC that I want UTF-16. Alternatively I want a different method that uses binary and not text.