[imp] Message attachment size can not exceed 2M??

[Matjaz Kljun]

Hi everybody.

I can't increase the attachment size in IMP

My php.ini  has the following entry:
    upload_max_filesize = 6M

The appropriate variable in horde/imp/config/conf.php has the value:
    $conf['compose']['attach_size_limit'] = '6000000';

www.example.org/phpinfo.php (with the phpinfo() function) says
     file_uploads     On     On
     upload_max_filesize     6M     6M

I see this message under Attachment section when I'm in Compose window 
in IMP :
    (Maximum Attachment Size: 2,097,152 bytes)

But if I try to attach file bigger than 2M (and smaller that 6M) I get 
this error:
    There was a problem with the file upload: The attachment was larger 
than
    the maximum allowed size (6291456 bytes).

Is there something I'm missing?

I'm using
IMP v4.0.3
HORDE v3.0.4

lpmk