Why is the lib32asound2-plugins package not in Precise?

I tried fixing some issue I have with the game 'Trine' (no sound, complains about missing libasound_module_conf_pulse.so) by installing lib32asound2-plugins. But it is not available. . It is suggested by lib32asound2 though, which installs fine.

~/d/c/trine> sudo apt-get install lib32asound2-plugins
Reading package lists... Done
Building dependency tree
Reading state information... Done
Package lib32asound2-plugins is not available, but is referred to by another package.
This may mean that the package is missing, has been obsoleted, or
is only available from another source

E: Package 'lib32asound2-plugins' has no installation candidate