asterisk users - Sep 2006 - changed behaviour of status indication on incoming pri lines in asterisk 1.2?

Hi,
we were using asterisk 1.09 with bristuff 0.20 for quite a long time now.
With the release of Asterisk 1.2 we tried to update our servers.

Now, with Asterisk 1.2.5, patched with Bristuff 0.3.0-PRE-1k on a SuSE
10.1 (we use the official SuSe 10.1 RPM of asterisk) we get some strange
behaviour with our "Junghanns Single E1" Card.

On our old server we place a call from the ISDN network to any of our
registered SIP phones. The call comes in via the E1 card and if our
internal SIP phone is busy the caller hears the busy tone.

However, on the box running Asterisk 1.2.5, same hardware, same config,
the call is accepted by Asterisk, but if the callen phone is busy,
Asterisk CLI tells us that he is executing Busy(), but on the other end
we only hear silence for about 30 seconds. Then Asterisk hangs up and we
get a busy signal. We have same results with Congestion().
On SIP-to-SIP calls everything works fine.

The part in the dialplan is simple and looks like this :

/;try dialing
exten => _XXXX,1,Dial(Sip/${EXTEN},30,tT)
; timeout is over, Not available
exten => _XXXX,2,Hangup()

;Dialing returns busy
exten => _XXXX,101,Busy()

;extension does not exists (no route to destination)
exten => _XXXX,201,Congestion()

/So, now we found out that signalling on PRI lines works, if we replace
/
exten => _XXXX,101,Busy()/

with

/exten => _XXXX,101,Set(PRI_CAUSE=17)
exten => _XXXX,102,Hangup

/Does anybody have an idea why this behaviour is so different to our old
system?

Thanks for any help!