sieve question

I am trying to write a sieve recipe that rejects emails that has attachments that are not either pdf or tiff.  I found this

if header :contains "x-attached"
  [".exe",".bat",".js",".com",".cmd",".ini",".dll",".bas",".cpl",".drv",".inf",".sys",".pif"] {

  discard;
  stop;
}

in this tutorial http://wiki.fastmail.fm/index.php?title=SieveRecipes


So I tried:

if header :contains "x-attached"
 [".tiff",".pdf"] {
 fileinto "INBOX";
 stop;
} else {
 reject "Your message was returned because of the attachment type. Please don't send me any attachment that are not pdf or tiff format.";
}

However, it does not work.  The emails get rejected regardless of their attachment type. That is, emails with pdfs and tiffs attached get rejected.  Anyone know what am I doing wrong?  Any help would be greatly appreciated.

Thanks,

Richard
-- 
Richard Reina
Rush Logistics, Inc.
Watch our 3 minute movie: 
http://www.rushlogistics.com/movie

-- 
Linux Users Of Northern Illinois (Chicago) - Technical Discussion 
http://luni.org/mailman/listinfo/luni