No 2D panels, that's not a bug, it's an intentional design choice.
The gauges in Acceleration are ALL entirely 3D, made as integral parts of the Virtual Cockpit model, there's no chance those might be done in 2D, except than rewriting an entirely new set of gaues, expecially done for 2D.
The only ones "flat" are the glass gauges and they can be used to create a 2D panel or 2D pop-up windows, but you have to edit the panel.cfg by yourself, maybe using one of the available programs, like FS Panels Studio.
