This is a non-official release. The X-Fi drivers were modded to work with Audigy.
This software allows the hardware-accelerated EAX functionality of games to be enabled under Windows Vista.

    In response to ungrateful behavior of Creative, I decided to release a patched ALchemy for all models of Live! and Audigy soundcards.

    It was ready since its release in last March. I was just waiting the proper moment, when Creative would make a stupid move.

    A simple check for EAX5 was removed to enable Audigy support as well as a check for EAX4, to enable support for Live! cards.

Source: Creative Labs Forum