ntlm_auth

Hello Mr DEKOK, I have 3 forests Active directory. I try to implemente freeradius as proxy. I install fedora core 4, freeradius 1.0.1, samba, i join the first domain, try ntlm_auth on command line it is ok, i try with the 2 other forest the comman "ntlm_auth --username --domain and give the password it is ok, i can autenticate all the users on the three forest, but it doesn't work with ntradping. Do you think that i need certificat from my CA windows for freeradius? If yes, how can i tranform the certificat like this freeradius anderstand it? Thank you.