Asus M2400N integrated modem functional (at least partially)

After my latest kernel upgrade to 2.6.9 via the usual TuxMobil.org debian packages, I noticed that Alsa now finds naming the integrated modem. The modem is a softmodem integrated with the sound-card.
Relevant output from “lspci -v“:

0000:00:1f.6 Modem: Intel Corp. 82801DB/DBL/DBM (ICH4/ICH4-L/ICH4-M) AC'97 Modem Controller (rev 03) (prog-if 00 [Generic])
        Subsystem: Asustek Computer, Inc.: Unknown device 1716
        Flags: bus master, medium devsel, latency 0, IRQ 7
        I/O ports at e200 [size=256]
        I/O ports at e300 [size=128]
        Capabilities: [50] Power Management version 2

The Alsa module for the modem is snd_intel8x0m.
From “cat /proc/asound/cards“:

0 [I82801DBICH4   ]: ICH - Intel 82801DB-ICH4
                     Intel 82801DB-ICH4 at 0x1f800400, irq 7
1 [Modem          ]: ICH-MODEM - Intel 82801DB-ICH4 Modem
                     Intel 82801DB-ICH4 Modem at 0xe200, irq 7

Searching the net a bit established that a user-space daemon is needed, slmodemd, debian package sl-modem-daemon.
The default debian setup detected the Alsa driver automatically and linked /dev/modem to /dev/ttySL0.
I have this running:

/usr/sbin/slmodemd --alsa -c DENMARK hw:1

I write “at least partially” in the title, because I haven’t managed to get everything to work.
I can dial a number and the phone rings.
I can send a fax using efax. I haven’t tried receiving.
I can’t connect to the ISP I tried. If I dial the provider, there is no carrier and wvdial just retries repeatedly. A manual call to the number gets the modem just fine. For each dial attempt I get this in the system log:

codec_semaphore: semaphore is not ready [0x1][0x701300]
codec_write 1: semaphore is not ready for register 0x54

I have search high and low, but I have not been able to find a solution to this problem.
So, partial functionality at most.