verify signature from Windows and Ubuntu does not work

[Mike]

On Wed, 2010-11-24 at 16:33 -0800, Paul Richard Ramer wrote:
> Sat, 20 Nov 2010 09:07:13 +0100, Mike wrote:
> > I use IMAP for my mailbox and I am accessing this from Win/Outlook and
> > Ubuntu/Evolution.
> > 
> > When I get an email and I access it first with Outlook, then I can not
> > verify the signature anymore in Ubuntu as the whole email got detached
> > into a separate attachment.
> > 
> > How can I resolve this?
> > I could not find any options in gpg4win or kleopatra.
> 
> When you say that the e-mail got detached into a separate attachment,
> are you talking about the copy of the e-mail that is stored on your
> computer or the message that is stored on the mail server?

The procedure is as following:
1) I receive an email on the IMAP server (plain text only, no
attachment, but signed with gnupg)

2) In Outlook I see the email, there is no attachment

3) When I click on the email the signature gets verified, verification
successful

4) The verification process makes a new email, the old one is deleted (I
see this on the server) and the new one has the plain text as body and
the whole email (all headers, body and pgp-signature) as attachment
called winmail.dat.

5) This email can still be verified (gpg signature) in Outlook but it
can not be verified on any other client like evolution or thunderbird
(on win or linux)

All this happens on the server as I access it via imap only.

Is this standard behaviour or are there any options in Gpg4win?

Thanks,
Mike