How to map the # key to a command?

[Chris Green]

I can map the # key to do ^Xe 'manually' when running vile simply by
going to the colon prompt and entering 'map ', then entering # in
response to 'change this string' and, finally ^Xe in response to 'to
this new string'.  The # key then opens the file under the cursor for
editing.

However I can't seem to get the same result by entering the map
command in my .vilerc file.

What do I need in .vilerc to get # to 'edit file under cursor'?

-- 
Chris Green