Cannot send emails from other applications

I installed Gpg4Win in MS Outlook 2007.
When I try to send an email (with attachment) using Adobe Reader (i.e emailing the PDF file via outlook), it creates the new email message with attachment. When I enter the receiver address and click ‘Send’ button, the email message is not sent. It stays as it is.

I noticed that this new message created by Adobe Reader doesn’t have Gpg4Win plug-in icons in the toolbar.

Is there something that I can do to solve the problem. It happens not only with Adobe Reader, but also with other applications which create emails with attachments.