Yeah, its only seems to work with {ifnot}...{endifnot} tags...
in includes/template.php find if ($matches[1] == 'not') {
Replace with if ($matches[1] == 'not' || $matches[1] == 'no') {
then find '='.preg_quote($this->start).'if(not)?\s+([A-Z0-9_]+)'.preg_quote($this->end).'=Usi',
'='.preg_quote($this->start).'endif(not)?\s+([A-Z0-9_]+)'.preg_quote($this->end).'=Usi',
Replace with '='.preg_quote($this->start).'if(not?)?\s+([A-Z0-9_]+)'.preg_quote($this->end).'=Usi',
'='.preg_quote($this->start).'endif(not?)?\s+([A-Z0-9_]+)'.preg_quote($this->end).'=Usi',