I tried to follow the instructions, but when using the module-assistant method, I got an error:

─────────┤ module-assistant, interactive mode ├─────────────┐
│ Build of the package alsa-source failed! How do you wish to
│ proceed?
│
│ VIEW Examine the build log file
│ CONTINUE Skip and continue with the next operation
│ STOP Stop processing the build commands
| <Ok> <Cancel>
└──────────────────────────────────────────── ──

Examiing the log file show everything working fine until I get the following errors:

make[5]: Leaving directory `/usr/src/modules/alsa-driver/pcmcia/vx'
make[4]: Leaving directory `/usr/src/modules/alsa-driver/pcmcia'
make[3]: Leaving directory `/usr/src/modules/alsa-driver'
/usr/bin/make -C /lib/modules/2.6.20-16-generic/build
SUBDIRS=/usr/src/modules/alsa-driver
O=/lib/modules/2.6.20-16-generic/build CPP="gcc-4.1 -E" CC="gcc-4.1"
modules
make[3]: Entering directory `/usr/src/linux-headers-2.6.20-16-generic'
CC [M] /usr/src/modules/alsa-driver/acore/memalloc.o
In file included from /usr/src/modules/alsa-driver/acore/memalloc.c:1:
/usr/src/modules/alsa-driver/acore/memalloc.inc:1:26: error:
linux/config.h: No such file or directory
In file included from /usr/src/modules/alsa-driver/acore/memalloc.inc:13,
from /usr/src/modules/alsa-driver/acore/memalloc.c:1:
/usr/src/modules/alsa-driver/include/adriver.h:742: error: redefinition
of ‘jiffies_to_msecs’
include/linux/jiffies.h:268: error: previous definition of
‘jiffies_to_msecs’ was here
/usr/src/modules/alsa-driver/include/adriver.h:761: error: redefinition
of ‘msecs_to_jiffies’
include/linux/jiffies.h:290: error: previous definition of
‘msecs_to_jiffies’ was here
In file included from /usr/src/modules/alsa-driver/acore/memalloc.inc:13,
from /usr/src/modules/alsa-driver/acore/memalloc.c:1:
/usr/src/modules/alsa-driver/include/adriver.h: In function
‘snd_pci_orig_save_state’:
/usr/src/modules/alsa-driver/include/adriver.h:1099: error: too many
arguments to function ‘pci_save_state’
/usr/src/modules/alsa-driver/include/adriver.h: In function
‘snd_pci_orig_restore_state’:
/usr/src/modules/alsa-driver/include/adriver.h:1103: error: too many
arguments to function ‘pci_restore_state’
make[6]: *** [/usr/src/modules/alsa-driver/acore/memalloc.o] Error 1
make[5]: *** [/usr/src/modules/alsa-driver/acore] Error 2
make[4]: *** [_module_/usr/src/modules/alsa-driver] Error 2
make[3]: *** [modules] Error 2
make[3]: Leaving directory `/usr/src/linux-headers-2.6.20-16-generic'
make[2]: *** [compile] Error 2
make[2]: Leaving directory `/usr/src/modules/alsa-driver'
make[1]: *** [build-stamp] Error 2
make[1]: Leaving directory `/usr/src/modules/alsa-driver'
make: *** [kdist_image] Error 2

The sound moudules I was trying to compile were virmidi and ca106