Headphones problem!!

Hola.
I want to hear the music in the speakers and the next song in the Headphones.
I bought a "TARJETA DE SONIDO USB 2.0 EXTERNA 3D Virtual AC-3 5.1 " for the headphones.
I have in the PC a realteck ac97.
I have installed Asio4all in the windows Xp .
But it still not possible to use the headphones.
By the way: with virtualDJ works.
Any help ????
Paco
I want to hear the music in the speakers and the next song in the Headphones.
I bought a "TARJETA DE SONIDO USB 2.0 EXTERNA 3D Virtual AC-3 5.1 " for the headphones.
I have in the PC a realteck ac97.
I have installed Asio4all in the windows Xp .
But it still not possible to use the headphones.
By the way: with virtualDJ works.
Any help ????
Paco