I just purchased a '09 Accord EX and from what I see you can't add an OEM navigation to this model? Do I purchase an in-dash and if so, will the buttons like volume, folder, etc.. work with an aftermarket unit.

 

They have interfaces to get the steering buttons working with an aftermarket HU, I have not seen or even think there is an interface for what your talking about, assuming your talking about buttons that are on the dash.