Mirage, whats your gear, I might be able to give you better advice if I knew what you are working with.
For the CP 995, I focus with the spot metering, on something like the compas. That gives me a good focus on the panel, and meters off outside light.. I then set the flash mode for lightning bolt (fill flash for fast shutter speeds). I shoot the flash should go off and balance the light. If the flash doesn't go off, you will get a perfectly exposed outside with a black frame (the frame before the one pictured above).
With the D100 or the D30, I focus on the panel first using the back mounted AF button (star on the D30), then I would use a half press to meter off the outside again, compose. With the flash set to fill take the picture.
On the N90s, I would do similar. Set the focus mode to continous. Meter off the window, and find where I want to focus. Use the AF lock button. Frame, and have the falsh set to fill. Shoot
Now if push comes to shove, and your camera doesn't support anything like that I guess you could meter the window, and set it to manual mode. That way when you half press the shutter it won't change your exposure, but it will AF. Just make sure that you flash is set to fill flash.
I hope this helps a bit, I'm good at taking pictures, explaining them is another thing.
At worst, you screw up and die.