sieve_extprograms - double linebreaks at filtering

[Hajo Locke]

Hello List,

i have a problem when using sieve-plugin sieve_extprograms. I use 
dovecot 2.2.18 and bundled pigeonhole 0.4.6 (Ubuntu 14.04.3 LTS)

i have enabled sieve_extprograms and vnd.dovecot.filter to send mail to 
user-defined script and get changed content back.
My script previously was used with procmail and is working fine.
Using same script with vnd.dovecot.filter leads to odd behavior.
I already found out the problem itself:
By sending Mailcontent to filter-programm it seems that 
sieve/sieve_extprograms is adding additional linebreaks to every line of 
complete mail.
Please see this image to clarify: http://r31i.imgup.net/header8d56.jpg?l=de
Every lineending got additional windows-lineendings, which leads to 
problems with processing scripts.
Piping mails by procmail to same script is working without problems, 
because this mails are recieved "clean" without the "^M".

this is part of dovecot.conf:

plugin {
  sieve = ~/.dovecot.sieve
  sieve_plugins = sieve_extprograms
  sieve_extensions = +vnd.dovecot.pipe +vnd.dovecot.filter 
+vnd.dovecot.execute
  sieve_pipe_bin_dir = /usr/local/bin/
  sieve_filter_bin_dir = /usr/local/bin/
}

this is part of userscript ~/.dovecot.sieve:

require ["fileinto", "vacation", "variables", "envelope", "imap4flags", 
"vnd.dovecot.filter", "subaddress"];
if address "to" "te...@example.com"
{
    filter "my-script";
}

my-script currently just recieves and saves raw-data, so i could find 
difference between sieve and procmail mails.
What to do here? Is this a kind of bug of sieve/sieve_extprograms or i 
have to use additional parameters?

Thanks,
Hajo