Hi Bavor,
In case you still need the info, here's the config files that TessuMod uses (the part which is installed into the game):
<WoT game folder>\res_mods\configs\tessu_mod\tessu_mod.ini
<WoT game folder>\res_mods\configs\tessu_mod\tessu_mod_cache.ini
Here's the config files that TessuMod TeamSpeak plugin uses:
%APPDATA%\jhakonen.com\WOTTessuMod.ini
%APPDATA%\alsoft.ini
WOTTessuMod.ini contains settings which you can modify from TeamSpeak > Plugins > TessuMod Plugin > Settings.
alsoft.ini is a global configuration file for OpenAL Soft, which the plugin uses to position and playback audio. I'm assuming that this was the one you were looking for? You can open this also from TeamSpeak > Plugins > TessuMod Plugin > Settings > Audio > Advanced Settings.
The alsoft.ini file under "C:\Program Files\TeamSpeak 3 Client\plugins\tessumod_plugin" is not actually used at all, it is there so that the plugin can copy it to %APPDATA% in case it is not there yet.