Scanning header fields as they pass through proxy

Hi,
	I've finally modified HeaderFilter to add headers as requests pass
through the proxy but I want to be able to add different information based
on a particular (non-standard) header.  Looking through org\w3c\www\http\
reveals lots of methods for scanning particular fields but I haven't found a
function which just returns a particular header value (as a String) when
given the header name (as a String).

	Does such a function exist?  I've finished browsing through the 60
files in the directory which might have such a function but with no success.
Has someone already impemented the HeaderValue interface not to parse
anything but just to return the value?  HTTPString.java looks close but I
can't work out what it's trying to do.

Thanks

Craig