After installing, I do not see the option Actions->WirelessMail->Configuration...

If your mail was open when you installed WirelessMail, you need to close and re-open your mailbox to see the WirelessMail Configuration option under the Actions menu.

Mail is open if you have a link to it on your Notes Welcome page, and your Welcome page is open.  In this case, rather than temporarily change your welcome page, simply restart Notes if you don't see the WirelessMail configuration action. Also, some Notes mail notification programs keep your mailbox open in the background, in which case you should simply restart your workstation.

Also check the 'Other...' option on the Actions menu. The Actions menu shows 9 options, and WirelessMail may show off the main list.