Yeah, you need a plate or some shoulder feature for the axial load on that bearing to push up against in order to transfer the loads to the frame without putting stress on the powertrain shafts.
You can use your existing bearing retention screws on the bottom for this task (just make a clearance hole in your larger (existing) plate.
Here is what it would probably look like in cross section (blue is on the crossectional plane, black is behind it) the end result is a part that looks like a ring with a bolt circle in it. (Edit - The mark-up I did here is slightly off, but the concept is fine, just go to the next image)
…and a (bad) orthographic view, you could easily tie into the red standoffs (dashed line)