I've posted a new build for Private Messages in the downloads section (members only).

New Functionality Includes:-

• New option in "View Options" to optionally "Use Sender's Email" address when receiving notifications of a new message. (This option is disabled by default, and the notifications will use the portal admin's email by default).
• Re-worked the "View Options" screen to be grouped by functionality.
• Added some new preferences for a user to customise, including "Always Attach Signature", "Default Signature" and "Always Save Copy". Setting these will default the options when composing a message.
• Added a checkbox next to the group notification dropdown to optionally not send email notifications to the receipients in that group.

Thanks again for all your feedback!