What actually happened:
His attack arrived as planned, and I managed to shoot down his DS in the 6th round of the battle (whew!). Unfortunately, I hadn't had time to transfer my 304 large cargos down to the planet (I forget about them while banned), so I lost 67 of those :P  I ended up losing around a third of my forces, as planned, in the process of shooting down his 1,117 light fighters and death star.

Curiously, it turns out that when I was automatically unbanned at the end of the 24 hours, I remained in vacation mode, so my fears of having the rest of my fleet totalled were unfounded. It was kinda funny to be in vacation mode and still have a fleet out on a fleetsave, though :)

If all this hadn't happened I probably wouldn't have missed out on the DF though :.(
"At these space coordinates now float 3.340.800 metal and 2.258.400 crystal"