Setting ContentType for bidi language

[sorinh]

Hello
 
I try to send an email using IdSMTP and IdMessage components with Hebrew on body text.
I use those settings:

Code:

IdMessage := 'UTF_8';
If HaveAttachments then
  IdMessage.ContentType := 'multipart/mixed';
Else
  IdMessage.ContentType := 'text/plain';

When I add attachments the emails arrive ok,
Without attachments the body text is replaced with questions marks.
 
What I'm doing wrong?