most likely ACM0 is the USB device. it'd be pretty easy to tell -- unplug the USB device and then try to list the ports again. if it disappears, then that's the port, and the driver is up and running.
unfortunately, if the ACM0 is your device, but it doesn't seem to be working, triaging bugs in these drivers is left up to the community. very few of the additional USB drivers we ship as modules we directly support. they're largely there because they're easy to include and power users find them useful.
-mike