The 900 will read DRM-free BBeB, but won't read DRM'd BBeB, this was listed on the tech specs page for the 900 on the site. It was also discussed here in a couple of threads.
Since the books can't be liberated right now (and since BBeB isn't available DRM'd from sellers anymore, I doubt anyone will try to start now), you are stuck waiting for the ePub versions to become available.
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