This article gives additional information about the method of sending an E-Mail 
message via Outlook from within a Delphi application.

As listed in the original article, the vMail.Recipients.Add( string ) method is 
used to add an E-Mail address to the "TO:" field of the Outlook message.  More than 
one address can be added by repeatedly calling the "Add" method.  Addresses can 
also be placed within the "CC:" and "BCC" address fields by appending a type 
designation onto the end of the "Add" method as follows:

vMail.Recipients.Add( string).Type := olMailRecipientType
where olMailRecipientType can be one of the constants olTo, olCC, or olBCC and olTo 
= 1; olCC = 2, and olBCC = 3.  Not specifying a type defaults to "olTo:".

The programmer can also set a deferred deliver time/date, set the message 
Importance, set the message Sensitivity, and the message Voting Options as follows:
1   
2   vMail.DeferredDeliveryTime := TDateTime;
3   
4   vMail.Importance := olImportance
5   //where olImportance can be one of the constants olImportanceLow = 0, 
6   olImportanceNormal = 1, and olImportanceHigh = 2.
7   
8   vMail.Sensitivity := olSensitivity
9   //where olSensitivity can be one of the constants olNormal = 0, olPersonal = 1, 
10  olPrivate = 2, olConfidential = 3.
11  
12  vMail.VotingOptions := widestring 

where widestring can be 'Approve; Reject', or 'Yes; No', or 'Yes; No; Maybe'.
It may be possible to express other voting options but I have not experimented
with it.  The above three seem to be sufficient to cover most situations.