\def\ps@betty{\let\@mkboth\@gobbletwo
     \def\@oddhead{}\def\@oddfoot{{\protect \sf test-\sf\hfil\thepage\hfil}}\def\@evenhead{}\let\@evenfoot\@oddfoot}
\def\footer#1
{\protect\def\ps@betty{\let\@mkboth\@gobbletwo
     \def\@oddhead{}\def\@oddfoot{\sf#1-\sf\thepage
     \hfil}\def\@evenhead{}\def\@evenfoot{\sf#1-\sf\thepage
     \hfil}}}


