The microphone does not work

[Superfox_il_Volpone]

Dear Gentoo community,
the microphone of my desktop computer is mute, while it works correctly on Windows.
I have a desktop pc with two sound cards, a built-in and a Xonar (Asus Essence STX). I can see both the sound cards through alsamixer, and the audio playback works fine, being also able to configure it. However I am puzzled how to properly set the microphone. Trying to switch the input jacks & raising the volumes through alsamixer for both the sound cards did not work, as well using the Sound view from the Settings panel of Gnome.
I still do not understand which sound card should be used for the microphone. This is connected to the front panel, and not to the line-in of Xonar sound card. Is it possible that built-in sound card should be set for the recording and the xonar for the playback? If so, how to properly set this configuration?

Few configuration info:

• List of my sound cards according to arecord -l and arecord -L: http://pastebin.com/AxvXJYMi
  
• My devices, lspci -v : http://pastebin.com/VeV2bhEn . The built-in sound card is a Realtek chip integrated in the ASUS M5A97 R2.0: http://www.asus.com/Motherboards/M5A97_R20/
  
• cat /proc/asound/cards
  

  Code:

  [root@sebastian] /home/dean: cat /proc/asound/cards  0 [SB             ]: HDA-Intel - HDA ATI SB                       HDA ATI SB at 0xfeb00000 irq 16  1 [HDMI           ]: HDA-Intel - HDA ATI HDMI                       HDA ATI HDMI at 0xfea60000 irq 72  2 [STX            ]: AV200 - Xonar STX                       Asus Virtuoso 100 at 0xc000, irq 20

  
  
• ls-l /dev/snd/ http://pastebin.com/KDVnkWHR
  
• alsa.conf (default): http://pastebin.com/NBcQMCxy
  
• amixer: http://pastebin.com/Jvge8Dyc
  
• kernel configuration: http://pastebin.com/MKUAPBAG
  

Any idea how to proceed?

Thanks,
Dean

[AndrewAmmerlaan]