According to the schematic provided you can no longer use the test LED "L" as you'd use in Diecimila.
I think you are misreading the schematic. In EAGLE schematics, two "signals" with the same name are connected electrically, whether or not there is an actual line drawn on the schematic diagram (it's very common for "professional" schematics not to have all the wires actually drawn, although some designers consider it important to indicate "other connections to a net with some sort of special label. So if you look at the areas around PB5, you'll discover that the piece coming off of the AVR pin 17 and the piece attached to the LED and IO pin do have the same signal name and ARE connected. (image attached, if that works.)
As far as I know, the Seeeduino boards are 100% compatible with the official Arduino board pinouts (not counting the added features on the Seeed board.)
