Travelmate 5720 - ICH8 82801 Sound -> no Capture

I have an Acer Travelmate 5720 with an Intel 82801 sound card. While sound output is OK meanwhile (Gutsy Gibbon Tribe 5) sound capture isn't.

The Gnome volume panel shows me two options:
- HDA Intel (Alsa Mixer)
- Realtek ID 268 (OSS Mixer)

Both have a single slider called "Master". Controls for capturing, cd, line, microphone etc. are missing. I can capture sound using an external microphone but I'm not able to adjust any settings nor to open the internal mike. Strange crackling occurs.

Here is my setup:

lspci
00:00.0 Host bridge: Intel Corporation Mobile PM965/GM965/GL960 Memory Controller Hub (rev 03)
00:02.0 VGA compatible controller: Intel Corporation Mobile GM965/GL960 Integrated Graphics Controller (rev 03)
00:02.1 Display controller: Intel Corporation Mobile GM965/GL960 Integrated Graphics Controller (rev 03)
00:1a.0 USB Controller: Intel Corporation 82801H (ICH8 Family) USB UHCI Contoller #4 (rev 03)
00:1a.1 USB Controller: Intel Corporation 82801H (ICH8 Family) USB UHCI Controller #5 (rev 03)
00:1a.7 USB Controller: Intel Corporation 82801H (ICH8 Family) USB2 EHCI Controller #2 (rev 03)
00:1b.0 Audio device: Intel Corporation 82801H (ICH8 Family) HD Audio Controller (rev 03)
00:1c.0 PCI bridge: Intel Corporation 82801H (ICH8 Family) PCI Express Port 1 (rev 03)
00:1c.1 PCI bridge: Intel Corporation 82801H (ICH8 Family) PCI Express Port 2 (rev 03)
00:1c.2 PCI bridge: Intel Corporation 82801H (ICH8 Family) PCI Express Port 3 (rev 03)
00:1d.0 USB Controller: Intel Corporation 82801H (ICH8 Family) USB UHCI Controller #1 (rev 03)
00:1d.1 USB Controller: Intel Corporation 82801H (ICH8 Family) USB UHCI Controller #2 (rev 03)
00:1d.2 USB Controller: Intel Corporation 82801H (ICH8 Family) USB UHCI Controller #3 (rev 03)
00:1d.7 USB Controller: Intel Corporation 82801H (ICH8 Family) USB2 EHCI Controller #1 (rev 03)
00:1e.0 PCI bridge: Intel Corporation 82801 Mobile PCI Bridge (rev f3)
00:1f.0 ISA bridge: Intel Corporation 82801HEM (ICH8M) LPC Interface Controller (rev 03)
00:1f.1 IDE interface: Intel Corporation 82801HBM/HEM (ICH8M/ICH8M-E) IDE Controller (rev 03)
00:1f.2 SATA controller: Intel Corporation 82801HBM/HEM (ICH8M/ICH8M-E) SATA AHCI Controller (rev 03)
00:1f.3 SMBus: Intel Corporation 82801H (ICH8 Family) SMBus Controller (rev 03)
02:00.0 Ethernet controller: Broadcom Corporation NetLink BCM5787M Gigabit Ethernet PCI Express (rev 02)
04:00.0 Network controller: Intel Corporation PRO/Wireless 3945ABG Network Connection (rev 02)
0f:06.0 CardBus bridge: Texas Instruments PCIxx12 Cardbus Controller
0f:06.1 FireWire (IEEE 1394): Texas Instruments PCIxx12 OHCI Compliant IEEE 1394 Host Controller
0f:06.2 Mass storage controller: Texas Instruments 5-in-1 Multimedia Card Reader (SD/MMC/MS/MS PRO/xD)
0f:06.3 Generic system peripheral [0805]: Texas Instruments PCIxx12 SDA Standard Compliant SD Host Controller

 amixer
Simple mixer control 'Master',0
  Capabilities: pvolume
  Playback channels: Front Left - Front Right
  Limits: Playback 0 - 64
  Mono:
  Front Left: Playback 52 [81%] [-12.00dB]
  Front Right: Playback 52 [81%] [-12.00dB]
 lsmod|grep snd
snd_hda_intel 263712 4
snd_pcm_oss 44672 0
snd_mixer_oss 17664 1 snd_pcm_oss
snd_pcm 80388 2 snd_hda_intel,snd_pcm_oss
snd_seq_dummy 4740 0
snd_seq_oss 33152 0
snd_seq_midi 9600 0
snd_rawmidi 25728 1 snd_seq_midi
snd_seq_midi_event 8448 2 snd_seq_oss,snd_seq_midi
snd_seq 53232 6 snd_seq_dummy,snd_seq_oss,snd_seq_midi,snd_seq_midi_event
snd_timer 24324 2 snd_pcm,snd_seq
snd_seq_device 9228 5 snd_seq_dummy,snd_seq_oss,snd_seq_midi,snd_rawmidi,snd_seq
snd 54660 17 snd_hda_intel,snd_pcm_oss,snd_mixer_oss,snd_pcm,snd_seq_oss,snd_rawmidi,snd_seq,snd_timer,snd_seq_device
soundcore 8800 1 snd
snd_page_alloc 10888 2 snd_hda_intel,snd_pcm

uname -a
Linux becconmobil 2.6.22-12-generic #1 SMP Sat Sep 22 18:14:28 GMT 2007 i686 GNU/Linux

Linphone brings up the following error messages which might be of help:

ALSA lib conf.c:3510:(_snd_config_evaluate) function snd_func_refer returned error: No such file or directory
ALSA lib conf.c:3982:(snd_config_expand) Evaluate error: No such file or directory
ALSA lib pcm.c:2144:(snd_pcm_open_noupdate) Unknown PCM default
ALSA lib confmisc.c:1286:(snd_func_refer) Unable to find definition 'defaults.pcm.dmix.device'
ALSA lib conf.c:3510:(_snd_config_evaluate) function snd_func_refer returned error: No such file or directory
ALSA lib conf.c:3982:(snd_config_expand) Evaluate error: No such file or directory
ALSA lib pcm.c:2144:(snd_pcm_open_noupdate) Unknown PCM default
ALSA lib confmisc.c:1286:(snd_func_refer) Unable to find definition 'defaults.pcm.dmix.device'
ALSA lib conf.c:3510:(_snd_config_evaluate) function snd_func_refer returned error: No such file or directory
ALSA lib conf.c:3982:(snd_config_expand) Evaluate error: No such file or directory
ALSA lib pcm.c:2144:(snd_pcm_open_noupdate) Unknown PCM default
ALSA lib confmisc.c:1286:(snd_func_refer) Unable to find definition 'defaults.pcm.dmix.device'
ALSA lib conf.c:3510:(_snd_config_evaluate) function snd_func_refer returned error: No such file or directory
ALSA lib conf.c:3982:(snd_config_expand) Evaluate error: No such file or directory
ALSA lib pcm.c:2144:(snd_pcm_open_noupdate) Unknown PCM default
ALSA lib confmisc.c:1286:(snd_func_refer) Unable to find definition 'defaults.pcm.dmix.device'
ALSA lib conf.c:3510:(_snd_config_evaluate) function snd_func_refer returned error: No such file or directory
ALSA lib conf.c:3982:(snd_config_expand) Evaluate error: No such file or directory