[Typo3] Direct Mail : mailgroup mails have image problem, using manual list no problem ?

[W van Bruggen]

Hello list,

i've ran into a weird problem that i cant seem to figure out. I've set
up directmail with some groups. When i compile a page and continue to
the 'Mass send e-mail' page, i select which group i want the mail to
be delivered to. The images in it are broken though :

for example :
<table background=3D"cid:part2.8aa3ccbdda99c9f36f37f8abf56c4f5a_MID1=15_t9"
cellpadding=3D"2" cellspacing=3D"0" style=3D"border-top:1px=solid
#000000;" width=3D"100%" height=3D"15">

will not load this image :
------------part_1_434a26132db52
Content-Type: image/gif
Content-ID: <part0.8aa3ccbdda99c9f36f37f8abf56c4f5a_MID115_t9>
Content-Transfer-Encoding: base64

I've been looking through the mailarchive (well, at least all i have
since beginning of this year because the archive is not on typo3.org
anymore) and could only find something similair happening with
sr_direct_mail_ext, which i dont use.

Another strange thing is setting a list manually in the 'Send mail -
list of emails' option does send the images correctly. The encoding of
those mails are base64, opposed to the 'Content-Transfer-Encoding:
quoted-printable' when i send to a specific group.

Is this is a bug in the directmail module? Has anybody ran into this
problem before, and has a solution?
Using 3.7.0 with 'direct_mail' 1.0.8

greets,
Wietse van Bruggen