This behaviour is controlled by server A, so that's where to put in
the fix.
But there is actually no problem at all -- all parties are acting in a
conforming manner. Server A "may" do the HTTP-EQUIV thing, but it's
not required:
http://www.w3.org/pub/WWW/MarkUp/html-spec/html-spec_5.html#SEC30
HTTP-EQUIV
binds the element to an HTTP header field. An HTTP server
may use this information to process the document. In
particular, it may include a header field in the responses to
requests for this document: the header name is taken from
the HTTP-EQUIV attribute value, and the header value is
taken from the value of the CONTENT attribute.
Dan