/// <include file='>' path='[@name=""]'/> failure

[sharpener]

I'm new to C# and to newsgroups, so please bear with a possibly foolish
query. I'll try to be sensible.

The results of /// <summary> ... </summary> etc. appear immediately in the
Object Browser, as advertised. But when I try to get the same result with
/// <include> ..., no joy.

Having spent the better part of 2 days in a textbook-help-and-msdn search,
I'm stumped, so I've isolated the problem in a solution consisting of nothing
else.

I've ensured that the project (.csproj), class (.cs), included file (*.txt),
and xml (.XML) files are all in the same folder. Further, the included
filename is correct: confirmed by mis-typing the name, building the project
and observing the Error List. Strangely, mis-typing the path leading to the
target text within the included file produces no error.

The same text works correctly when copied from the included file and pasted
ahead of the class definition with /// prefixes.

Hoping someone can help.
--
to be sharp or not to be, that is the question