[imp] opening a popup window upon login?

[Wes Johnston]

I am running horde/imp under SME server 5.6.  I've created a menu option under "login tasks" called 'open_calendar' and can set and reset the checkbox from the options page.  All is well at this point... my users can decide if they want the company calendar to popup when they log in.... now to *do it*.

In the mailbox.php file, i've added the following lines up near the "show_last_login" code.
    if ($prefs->getValue('open_calendar')) {
        Horde::raiseMessage(sprintf(_("You selected to open the calendar at login")), HORDE_MESSAGE);        
    }
which displays a simple banner if the person has selected to open calendar or not.  my question is how do I make it open a new browser popup window upon login instead of displaying the above message?  I know this is probably a trivial call to the horde app, but I'm just not familiar enough with it to figure out on my own.  I would love for my popup window to open just like the compose window does, but automatically on login.

In other sections of my code, I have created links to the calendar (which has been modified to accept the horde session ID as a valid login - neato) like this:
<?= Horde::url("/cgi-bin/calendar/calendar.pl?template=default.html&fromTemplate=login.html&view=Four-Week&command=login&calendar=default",0,1) ?>

THanks, sorry if this is a "so simple, it's stupid" question.

Wes