There are three options
I've seen people use for protecting their camera in a Watershed Ocoee:
1. A specialty camera big (IE LowePro or ThinkTank) inside the Ocoee.
The problem here is that as your camera equipment evolves over time,
the bag doesn't and becomes a limiting factor if you acquire more or
2. Watershed Camera Liner. This liner works but the padding is pretty
thin, and while the fleece material feels nice, it retains any water
that drips into the bag. Rather expensive for what it is too.
3. Home-made liner fashioned from a standard closed cell foam
sleeping pad. Cheaper, doesn't soak up water and has thicker padding
than any other option. Mitch Sitnik came up with this genius idea.
It's simple to make. Just cut one large piece slightly narrower than
the Watershed Ocoee. Make it long enough so it can hold your camera and
wrap around to close the top when the bag is rolled. Then cut two
pieces for each end.. Tie/Sew the circles to each edge of the main
piece so it wraps around, but doesn't close all the way. That's it, now
you have the best option for very little money and a bit of elbow
grease. I just throw in my camera body with lens attached, and keep
lenses and items in leather lens bags that come with any higher end