(Resolved in 5.0.0)
In all versions of Outlook to date, when applications create E-Mail messages via the so called MAPI interface, Outlook will not notify third-party addins about this, thus not allowing them to "hook" into the process before the message gets sent. As a result Lucatec® Mask would neither apply any context-dependent message options (i.e. sender, signature, save target) nor would its Message Options button appear on the toolbar allowing you to set these options yourself. A slight improvement in Outlook 2007 and later did at least allow the addin's button to be available on the "Ribbon" control but it was still not possible to automatically apply any message options right on message creation.
A partial workaround was introduced in version 2.2.0. However, it only worked on mails sent from Word or Excel and only for Office 2003 or older. This was finally resolved for good in Lucatec® Mask 5.0.0. The addin is now able to process all messages that open in a new message window in Outlook regardless of what application created them.
There is currently no way to process messages that are created and sent without user interaction.
Please note that Outlook still prevents the insertion of signatures for messages created by other applications. We are investigating possible workarounds to this for the upcoming 6.0 release.