Juno

1. On the drop down menu "Options", choose "Email Options.."
   
2. Under "Show Message Headers", select the "full" option.
   
3. Click the OK button to save the setting.

Juno version 4+ can display MIME and HTML email, but does not provide a way of Viewing the HTML Source for the message within Juno. To get the full source, including HTML codes:

1. In the Juno mail client, click "file" and then "Save Message as Text File.." (ctrl-T).
   
2. Give the file a name which you will remember (many people save temporary files to the desktop).
   
3. Double-click on the resulting file and then cut-and-paste the contents to the the form web-site.
   
4. After the spam is reported you can delete the temporary file or just over-write it the next time you need to report spam.