(sigh)... that plate DOES mount under the 3x5 cover UNDER the seat. and yet it is STILL tapping into the hyds of the machine produced by that front pump.
At this point you REALLY REALLY REALLY should STOP. and buy an owners and shop service manual, and master parts catalog for you machine so you can better understand how all the bolted on parts work with each other.
there is a plumbing manifold from that pump that then connects to the trans.. thru some more dubious plumbing thru the base of the trans.. to yhe center section, and then upt he casting to the top cover.. where it then interacts with that blank plate and the cyl/valves bolted underneath the hyds cover.