Maybe this is not possible with the plugin but it is an enhancement. In my opinion, there is no need to have a second open file dialog. It would be good to have this merged in the normal open file dialog. If you really want to change to bin, oct, or hex, you can do it, inside the open file dialog. If not, then you don't need to.
If this is not possible, maybe after the move from Oracle to Apache, it could be good, to have this plugin merged into the core, so that you can change the open file dialog logic.
Cheers
Chris