Apple’s Achilles’ Heel shows up in many ways. They absolutely love designing this quirkiness into everything, as simply spending more, or sticking with all things Apple seems to be the only solution.
Aha! That’s the design. And it’s a really cheesy way of doing things.
Let’s fix it.
First, iTunes. I’ll expose the cheese in this little application: it ignores anything that doesn’t have an Apple logo on it. Simple solution? Navigate to the itunes library and manually transfer the file. For the Sansa, you need a compatible file. Format 4 should be an Audible aa format file. I am hoping that itunes isn’t trying to give you an m4b protected audiobook format. Heck, they cant even use the same file extension as the rest of us.
Audible have been working on making audiobooks more universally accessible. Going to the Format 4 media preceded their new DRM system, one that allows the device itself as the platform, simpler than the Windows PFS (Janus or WMDRM-10) system. The key here is to first authorize your Sansa using the Audible Manager application. Then, should you use basic MSC or MTP for transfer, the file will play for you.
The Zip places all Audible books under the Audiobook / Podcast node automatically for you.
If I recall correctly, authorizing the Sansa on a Windows PC is the only hurdle you’ll need to jump. Go to Audible.com, log in, download the application, plug in your Sansa, and authorize the device. From this point on, it should handle your Audible books with ease.