Well this is crap, their special driver only works on the Audigy 2 and higher. The A1 cards are exactly the same save 24bit audio processing capabilities, so the A1 cards are fully capible of doing EAX 4.0 and OpenAL. This is complete and utter crap from Creative, they have no reason to shaft A1 owners like this other than pure greed. Thankfully previous A2 drivers at least have been hackable to be allowed to be used on A1 cards.
On a related note, this is the result of Creative's suit against id claiming ownership of the Carmack's Reverse technique. I'd like to bash CL over this, but honestly, I'm a headphones user, so I actually want Doom3 to support EAX so that I can have 3D audio with my headphones.