Duemilanove Manual Power Selection

Is there a way to have a USB connection to a Duemilanove, but get the power by connecting a different 5V power supply to 5V on Duemilanove? In other words, can I disable auto power selection?

I want the convenience of USB programming, but dont want the power to come from the PC.

Alternatively, can I do this by using a USB TTL-232 cable TTL-232R 3.3V (from adafruit.com)? http://www.adafruit.com/index.php?main_page=product_info&products_id=70. If I do this, which pins of the TTL cable must be connected to which pins of the Duemilanove?

Duemilanove GND and 5V would come from an alternate power source.

Thanks.

Remove R11 and connect Vin to the 5V line. Then you can power the board direct from a regulated 5V.