asterisk users - May 2006 - A call from a call file always does a redial?

I have an issue with the Snom 360's (any firmware) and asterisk call
files.  When you setup a call using a call file from Asterisk and the call
is connected, Asterisk will start to redial the call after about 5 minutes
when the conversation is already ongoing. (Annoying and it can only be 
avoided by disabling call waiting)

I tried to reproduce the problem with a GrandStream phone and a Sipura
ATA, it doesn't occur.

I guess these are 2 problems :

1) The callfile specifies that a call should not be retried, still * does
a redial

2) I *guess* the Snom is returning a different signal than other phones
when the call is answered up making Asterisk believe that the call 
never succeeded.

I registered this as a bug in mantis previously but nobody was able to 
reproduce, I know found out that it is only happening when using a 
Snom 360 as client.