asterisk users - Jun 2005 - second isdn line doesn't work with avm c2 card

I have an asterisk installation connected to 2 isdn lines via an AVM C2
card.

modules seems to load well, lsmod gives :

c4                     19588  4
b1                     24192  1 c4
capidrv                28468  2
isdn                  134604  9 capidrv
slhc                    7552  1 isdn
capi                   18112  4
capifs                  6024  2 capi
kernelcapi             46112  4 c4,b1,capidrv,capi


'capi info' from * console returns correctly :

Contr1: 2 B channels total, 2 B channels free. 
Contr2: 2 B channels total, 2 B channels free.

(chan_capi-0.3.5)


I'm doing outgoing calls in this way :

(extensions.conf file)

exten => _0X.,1,Dial(CAPI/0227006796:b${EXTEN:1}) 
exten => _0X.,2,Congestion


I can use only the first controller, on the third call out the line is
occupied, asterisk console says :

Connected to Asterisk 1.0.7


    -- Executing Dial("SIP/annap-5827",
"CAPI/0227006796:b3282045") in
new stack
    -- Called 0227006796:b3282045
    -- CAPI[contr1/0227006796]/129 is making progress passing it to
SIP/annap-5827
    -- CAPI[contr1/0227006796]/129 is ringing
    -- CAPI[contr1/0227006796]/129 answered SIP/annap-5827
    -- Executing Dial("SIP/sonian-db55",
"CAPI/0227006796:b3394180") in
new stack
    -- Called 0227006796:b3394180
    -- CAPI[contr1/0227006796]/130 is making progress passing it to
SIP/sonian-db55
    -- CAPI[contr1/0227006796]/130 is ringing
    -- CAPI[contr1/0227006796]/130 answered SIP/sonian-db55
    -- Executing Dial("SIP/nuccia-2fb1",
"CAPI/0227006796:b035343") in
new stack
    -- Called 0227006796:b035343
  == No one is available to answer at this time
    -- Executing Congestion("SIP/nuccia-2fb1", "") in new
stack
  == Spawn extension (generale, 0035343, 2) exited non-zero on
'SIP/nuccia-2fb1'
  == Spawn extension (generale, 03394180, 1) exited non-zero on
'SIP/sonian-db55'
  == Spawn extension (generale, 03282045, 1) exited non-zero on
'SIP/annap-5827'




/etc/asterisk/capi.conf 

msn=0227006796 
incomingmsn=* 
controller=1,2 
mode=immediate 
softdtmf=1 
context=incoming 
callgroup=1 
devices=4