How to set a text theme for plymouth?

I have Ubuntu 12.04 (beta) and I want to set a text theme for Plymouth, because I need to read what commands the PC is running on shutdown (because it freezes when I shutdown it), but the method I found googling ( How do I change the plymouth bootscreen? ) is not working: this is the ouput of update-alternatives --list default.plymouth:

user@host:~$ update-alternatives --list default.plymouth
/lib/plymouth/themes/solar/solar.plymouth
/lib/plymouth/themes/ubuntu-logo/ubuntu-logo.plymouth
user@host:~$ 

And the text themes are not displayed. How can I set a text theme for Plymouth?

Try this:

sudo update-alternatives --install /lib/plymouth/themes/default.plymouth default.plymouth /lib/plymouth/themes/ubuntu-text/ubuntu-text.plymouth 10

and then

sudo update-alternatives --config default.plymouth

Use the following to select the splash theme:

sudo update-alternatives --config default.plymouth

And use the following to select the text-theme:

sudo update-alternatives --config text.plymouth