How to initialize controls in a custom outlook property page ?

[sta-17kk]

I've downloaded the Vertoner sample for Outlook just to understand how
to add a CommandBar and a custom property page.

The property page works well, the apply button become available when a
change occurs, etc... The problem is that the OnInitDialog event isn't
fired.

With spy++ i saw that no WM_INITDIALOG message are sent to the page.

I've tried to catch the WM_ACTIVATE message (because some appear when a
property page is displayed) the same way it is with WM_INITDIALOG but
the function is never called.

So, how can i detect than an user is displaying my property page to do
some initialization ?

Thanks in advance for your answers

ps: I'm working with Visual Studio in c++ with the unmodified Vernoter
sample.