Ax25 problems...

Hi ! I'm trying to do packet activity with my laptop with Suse 6.4. I've succesfully installed Tom Sailer's usermode soundmodem and it works: it decodes packet coming from the air and it is heard by other stations. But I coulnd't manage to have a real connection: using the 'call' program i can tx only what i type on the keyboard,without any connection request and so... I'm using libax25,ax25-apps and ax25-tools installed by rpms. How can I set my system to work in "connected mode" (i think that this is the problem) ?? I've tried "echo 1 >/proc/sys/net/ax25/ax0/connection_mode without results. Usually that file contains 2 on my system. Thanks for your help, Pietro