cdc-acm device won't reopen

With linux-image-2.6.10-4-686 2.6.10-25.2 (and earlier 2.6.10's), I can use
cdc-acm device after boot (ISDN modem), but if I disconnect, the modem stops
accepting modem commands. Also, if I unplug it and then plug it back it, it
doesn't get assigned to /dev/ttyACM0 anymore (I get a message in
/var/log/messages "cdc-acm: module is already loaded" or something like it).

Everything works fine with linux-image-2.6.11-1-686 2.6.11-0.2 (except that I
have to use "i8042.noacpi"), and I'm using it now without any problems so far.

I believe the following is the fix:
  http://www.spinics.net/lists/kernel/msg343522.html

Can this be backported to Hoary kernel? (I'm willing to test as well, and I'm
downloading linux-source-2.6.10 already, but that will take a couple of hours)

Though, according to http://kernel.org/pub/linux/kernel/v2.6/ChangeLog-2.6.11,
there was another fix for cdc-acm as well.