Ca'n't perform properly 2 servers connection via IAX

hello every body
I have 2 PC with mandriva 2006
one is running asterisk (say server A futher on)
the other is running asterisk 1.2.3 ( say server B futher on)
The server A has no digium card (no lnk to pstn)
The server B has a digium 110P

My configuration contains SIP softphne, H323 phone, and pstn phones
The SIP phone are register with the server A
The H323 phones are register with server B (using Gnugk gateway)
with this configuration, i have modified configuration files for the gnugk gateway.
And now it is possible to call from servr A the H323 phones
and the H323 phones can call a customized service created on the server A
(that’s work)

NOW I would like to do the following
From server A I would like to call PSTN phones (via serverB)
From PSTN Phones , I would like to reach the customized services (created on serverA)

I have read the 2 pages … +2+servers±+dual+servers
and have tried to use this with IAX
I have not succedeed to perform this using AIX. My configuration is

type=friend ; appel entrant du RTC via timsip (IP adresse of serverB)

exten => _02XXXXXX,1,Dial(IAX2/serverB/${EXTEN:1},30,r)

and for server B

host=IP addresse of serverA

exten => *800, 1,Dial(IAX2/serverA/${EXTEN:1},30,r)

Nothing works
I have tried to set up debug using the cli command
iax2 debug but there is nothing on the console

I do not understand what hapens

so if I could get som help, at least to transfer from serverB toward serverA a sp?cific call from PSTN phones
thanks a lot