Abaixo tenho um código que funciona para mim.
` % Create separate counters for appendices and annexes
\newcounter{appchapter}
\newcounter{annchapter}
%==============================================================================
%%% Redefinicao do comando \appendix para mostrar 'Apêndice' ou 'Anexo'
%%% no Sumario
%==============================================================================
\renewcommand{\appendix}{%
\cleardoublepage
\providecommand\anexoautorefname{appendix}
\setcounter{section}{0}%
\def\Hy@appendixstring{appendix}% %%novo string no *.toc, para fazer o hyperlink funcionar
\def\anexo{%
@ifundefined{chapter}%
{\gdef\theHsection{\Alph{appchapter}}}%
{\gdef\theHchapter{\Alph{appchapter}}}%
\xdef\Hy@chapapp{\Hy@appendixstring}%
\gdef@chapapp{\appendixname}%
\addtocontents{toc}{\SetAppendixTocName{\appendixname}}%
\gdef\thechapter{@alph\c@appchapter}% <-- Use appendix counter
}
\setcounter{appchapter}{0}% <-- Reset appendix counter (moved outside of \anexo)
\stepcounter{appchapter}% <-- Increment appendix counter (moved outside of \anexo)
\anexo
}
%==============================================================================
%%% Acrescenta o comando SetappendixTocName ao toc
%==============================================================================
\DeclareRobustCommand{\SetAppendixTocName}[1]{\gdef\AppendixTocName{#1}}
%==============================================================================
%%% Novo comando: \annex
%==============================================================================
\newcommand{\annex}{%
\cleardoublepage
\providecommand\anexoautorefname{annex}
\setcounter{section}{0}%
\def\Hy@appendixstring{annex}% %%novo string no *.toc, para fazer o hyperlink funcionar
\def\anexo{%
@ifundefined{chapter}%
{\gdef\theHsection{\Alph{annchapter}}}%
{\gdef\theHchapter{\Alph{annchapter}}}%
\xdef\Hy@chapapp{\Hy@appendixstring}%
\gdef@chapapp{\nameannex}%
\addtocontents{toc}{\SetAppendixTocName{\nameannex}}%
\gdef\thechapter{@alph\c@annchapter}% <-- Use annex counter
}
\stepcounter{annchapter}% <-- Increment annex counter (moved outside of \anexo)
\anexo
}`