If you do not have your Liquid Mix installer DVD available, you can install the emulations using the Liquid Mix emulations installers. You can download the emulations installers for both Mac OS and Windows at the links below - scroll down to "Liquid Mix Emulations (44.1kHz - 96kHz) ":
Liquid Mix
http://www.focusrite.com/support/software/liquid_mix/
Liquid Mix 16
http://www.focusrite.com/support/software/liquid_mix_16/
Liquid Mix HD
http://www.focusrite.com/support/software/liquid_mix_hd/
NB: The emulations files are exactly the same on both Mac OS and Windows and for all Liquid Mix products.