The Splash Pan can be removed from the Omni Spindle Housing quite easily.
Once the Platen and Spindle have been removed, look under the Splash Pan to locate the attachment screws. Using a 3/32″ Allen key loosen these screws.
Once loosened, the Splash Pan will lift off the Spindle Housing easily. Unless it’s corroded into place, in which case a couple light shots of WD40 and gentle tapping should loosen it.
More information about corrosion in the discussion and photos about Omni Design Flaws section.
Here’s a photo of the Splash Pan bottom once it has been removed from the Spindle Housing. Notice the signs of corrosion in the collar that surrounds the Spindle Housing.