The simplest solution is yes, to create a new AV command, and map it to an existing non-pluto remote, like DVD (you'll be able to do this when you map inputs on your TV), if you select anything other than External Device, then it will simply add a new embedded device to the TV, and the media plugin will change the remote to that device. The closest match out of the box is the non-pluto DVD remote. Your TV will need to implement the move up, move down, move left, move right, enter, and back commands so that the arrow buttons will work.
Should you wish to change the remote to something not covered in that media type, you'll need to edit the Netflix child device of your TV's device template…and add an entry to "Design Objects to use as Remotes" in the template. There is, for example, a Hulu remote that can be used that has the requisite buttons.
Should you want to implement a new remote, you'll need to watch my screencasts.