UZ117 and CB79 have been confirmed as members of the family by both Pinilla-Alonso et al. 2008 
 
 Title: 	 Visible spectroscopy in the neighborhood of 2003EL{61} 
 Authors: Pinilla-Alonso, N.; Licandro, J.; Lorenzi, V. 
 Publication: Astronomy and Astrophysics, Volume 489, Issue 1, 2008, pp.455-458 

  
 and Schaller & Brown 2008  

  
 Title: Detection of Additional Members of the 2003 EL61 Collisional Family via Near-Infrared Spectroscopy 
 Authors: Schaller, E. L.; Brown, M. E. 
 Publication: The Astrophysical Journal, Volume 684, Issue 2, pp. L107-L109. (ApJ Homepage) 

  
 You need both, a neutral visible spectrum and a nearIR with deep water ice absorption bands. 

 As far as I know, the actual confirmed members are 7 (8 only if you consider Haumea's biggest satellite)