activating a button

[Davina Armstrong <davina lickey com>]

I want write a dialog box that does the following:

It has a GtkEntry and a GtkButton.  When it first appears, the GtkEntry
has the focus.  The user types in the GtkEntry and hits Enter, which -
and here's my problem - activates the GtkButton.

When I hit Enter, the GtkEntry "activate" event is triggered.  I can
either make the "activate" event call my button callback function, or I
can make it call gtk_button_clicked(button), both of which work, but
fail to give the user the visual feedback of the button being clicked. 
Can anyone tell me how to accomplish this?

Thanks!
Davina