The purpose behind this is, to be already informed during addressing if someone is out of office and how long, instead of sending the mail first an then being notified afterwards.

It is a request from our IT management, because MS Exchange seems tp provide this function.

You can use Extracomm's OOO Status Query Sidebar Widget to query other people OOO status before sending email.

http://blog.extracomm.com/Extracomm/blog.nsf/dx/How-to-query-other-people-out-of-office-status-in-Lotus-Notes.htm

In addition, you can also incorporate the query function in your mail template by making use of OOOManager LotusScript Library.

To retrieve other people OOO status, you can use methods:

• GetOOOStatus(username_or_groupname As String)
• GetOOOStatusXML(username  As String)

http://blog.extracomm.com/Extracomm/blog.nsf/dx/get-set-Out-of-Office-profile-programmatically-in-Lotus-Notes.htm