I really hope that this one will work for you.
It seems there are 2 versions of this modem floating around
Here's the one I have (looks the same as the one that kazade linked on his blog, but it doesn't work since it is a pure softmodem)
Bus 001 Device 004: ID 0572:1300 Conexant Systems (Rockwell), Inc. SoftK56 Data Fax Voice CARP
According to a user on kazade's blog, this is the output of the modem that kazade has linked
Bus 001 Device 004: ID 0572:1340 Conexant Systems (Rockwell), Inc.
The zoom linked above also kinda looks the same, but with branding.
http://therandymon.com/index.php?/archi ... Linux.html
Basically the one I have is a softmodem which doesn't work out of the box...
What I've understood so far, the one that we need would be non-soft modem that shows up as
/dev/ttyACM0 when connected via usb