smtpd.comf: '... reject "message"' fails

My reading of smtpd.conf says that any reject action should be able
to take a message parameter. Yet the following line is rejected
with a syntax error message:

match mail-from rdns regex "\.t-online\.de$" reject "550 5.7.1 you don't accept our mail, so we don't accept yours."

Yet the same line without the string after the reject keyword works.

I spent some time digging in the grammar, but yacc just gives
me migraines. Should this in fact work? Or is the manpage
wrong.

--lyndon