anchor.diff:  
   process(f, 'content-language', Lang) ->
       sip_binary:any_to_binary(Lang);
  +
  +%% 20.14 Content-Length
  +%% http://tools.ietf.org/html/rfc3261#section-20.14
  +process(pn, <<"l">>, _Ignore) -> 'content-length';
  +process(fn, 'content-length', _Ignore) -> <<"Content-Length">>;
  +process(p, 'content-length', Bin) ->
  +    sip_binary:binary_to_integer(Bin);
  +
  +process(f, 'content-length', Length) when is_integer(Length) ->
  +    sip_binary:integer_to_binary(Length);
  +
   
   %% .....
   process(pn, <<"v">>, _Ignore) -> 'via';
  
positive.code:                                    {'authorization', <<"Digest username=\"Alice\"">>}, {'call-id', <<"callid">>},
                                     {'call-info', <<"<http://www.example.com/alice/photo.jpg>">>}, {'contact', <<"*">>},
                                     {'content-disposition', <<"session">>}, {'content-encoding', gzip},
                                     {'content-language', 'en'},
  
                                     {'content-length', <<"5">>}, {'via', <<"SIP/2.0/UDP localhost">>},
                                     {'from', <<"sip:alice@localhost">>}, {'to', <<"sip:bob@localhost">>},
  
negative.code:     append_params(TypeBin, Disp#sip_hdr_disposition.params);
  
  %% 20.12 Content-Encoding
  %% http://tools.ietf.org/html/rfc3261#section-20.12
  process(pn, <<"e">>, _Ignore) -> 'content-encoding';
  process(fn, 'content-encoding', _Ignore) -> <<"Content-Encoding">>;
  process(p, 'content-encoding', Bin) ->
  