[Dovecot] mime support for pigeonhole

[Tim Dickson]

is there any chance of rfc5703 (mime support/extension) being added to 
pigeonhole?
I am trying to filter mail with .exe and .zip attachments, to no success.
I have tried
*header :contains "x-attached" [".zip", ".exe"]
*but emails i'm getting don't have x-attached.
a sample snippet is below.

Subject: testa1
Content-Type: multipart/mixed;
  boundary="------------020304040002050407030900"

This is a multi-part message in MIME format.
--------------020304040002050407030900
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
Content-Transfer-Encoding: 7bit

this has a compressed file added a1


--------------020304040002050407030900
Content-Type: application/x-zip-compressed;
  name="pinglog.zip"
Content-Transfer-Encoding: base64
Content-Disposition: attachment;
  filename="pinglog.zip"


I have tried
*header :contains ["Content-Type","name","filename"] 
["application/x-zip-compressed",".zip",".exe"]*

but that doesn't work either.

I can't use body because that doesn't include the mime headers, so the 
only way I can see is to use mime (aka rfc5703)
I am using dovecot 2.1.8 with pigeonhole 0.3.3  (and am about to use 
dovecot 2.2.9 with pigeonhole 0.4.2 on another server)
If I'm just missing the point, or there is already support, please point 
me in the right direction.