--- sgml-tools-1.0.9/lib/SGMLTools.pm
+++ sgml-tools-1.0.9/lib/SGMLTools.pm
@@ -440,7 +440,7 @@
 
   create_temp("$tmpbase.3");
   system ("$main::progs->{SGMLSASP} $style $mapping <$tmpbase.2|
-      expand -$global->{tabsize} >$tmpbase.3");
+      expand -t $global->{tabsize} >$tmpbase.3");
 
   #
   #  If a postASP stage is defined, let the format handle it.