There are three versions of RS 3055 Upgrade Unabridged. Sounds like you need to get an updated copy. (DriveThruRPG or CatalystGameLabs should be able to provide you with that if you bought it from them).
The first was from FanPro and has a Wizkids copyright. This has the clan omni fighters, but is old and probably is missing some newer variants. (The newer PDF tend to introduce new variants, but I don't know specifically if the clan omni fighters got new variants.)
The second was from CGL and has a Topps 2009 copyright. This does not have the clan omni fighters at all. Presumably the version you are looking at.
The third was an updated PDF from CGL and has a Topps 2011 copyright. This is what the MUL and Sarna are referencing.