Unzip the ogc_sso.zip archive file to the following folder of your installation:
\omnigen\omniGenData
This will create the following subdirectory, which contains two .xml files:
\omnigen\omniGenData\sso
Note: As of Omni-Gen version 3.10.0 and higher, the two .xml files in this subdirectory are included in the release packaging (in \omnigen\OmniGenData\sso), which avoids the need to install these files manually.