I can't answer specifically about your combinations, but I have a PRS-350 and use ADE on Windows.
Most Sony's operate in a pretty similar way, and ADE is pretty similar on Windows and Mac.
So some comments based on that; one of them may work out for you.
You do need to install the Sony software as it includes a driver as well as the Sony Reader app itself.
Without that driver ADE won't recognize the Sony.
This doesn't seem to be your issue, as you have installed the Sony software.
You could try running ADE at the same time as Sony Reader in order to make sure the driver is running correctly.
There are lots of bugs in ADE2.0.
One of these means that the Sony/ADE/Overdrive combination won't work properly; eg for library books.
The only easy solution I have found to that is to use ADE 1.7.2 instead of v2.0.
That could solve your no-show issue as well.
Version 1.7.2, it is a little difficult to find, available on Adobe site for Windows and for Mac.
http://helpx.adobe.com/digital-editions/kb/cant-install-digital-editio ns.html
The forum software is sometimes corrupting the link above. There shouldn't be a blank in 'editio ns.html'. The following redirects to the same page: http://tinyurl.com/diged172
You should be able to do everything you did with ADE using Sony Reader instead.
Except: (1) it won't keep any library organization you have already done on ADE and (2) it won't work with other devices (such as you old reader if you are still using it as well).
You should be able to use ADE for most of the operations as you did before, just not for the copy to the Sony.
If you use ADE as before up to the copy to device stage, you can then 'sideload' the DRM .epub files from the Mac to the Sony using Finder (Explorer on Windows).
