printing on both sides...

["Mulley, Nikhil" <mnikhil corp untd com>]

Hi All,
 
I am using Fedora Core 1 , we have 'HP LaserJet 4100 MFP' as network printer  which is shared on a Windows Server , I was able to add to my Fedora , with the help of redhat-config-printer,
lately , our management added one dupleixer unit to the printer to print on both sides  , How do I enable print on both sides on my Linux Box , I tried on Google , may be I havenot exactly did searched what I wanted to .. :(
 
can any one please suggest me HOW-TO 
 
Thanks,
Nikhil.
 °v°
/(_)\
  ^ ^