Andrey,
If it works without BIOS, I don't see any reason why it wouldn't work with BIOS. Without knowing the specifics, basically, your interrupt handler becomes a Hwi. You probably have some init code that intializes the network chip, and that should be done in main() or prior to main(). The body of your code that process the data should be a TSK.
The way the interrupt is triggered without BIOS should be the same way its triggered with BIOS.
I know i'm simplyfing it, but really BIOS simply adds the ability to schedule things. The hardware should still work the same.
Judah