Attached is a quote for the swapping of the pump from the one with the tach sensor in it to the other pump. This should work, but I have to comment that I can not guarantee that it will. If this was my engine I would have no trouble doing this, but I am not going to mad at myself if it doesn't work correctly.
So we take the other pump, fabricate the triangle plate (I have the drawings from Volvo Penta) that allows the pump to go onto the engine. Replace the companion flange on the follower shaft to allow the new pump. And then take a tube set from an AQ170 cut off the pipes to allow the existing hoses connect to them (just like they do now).
Then you will have to buy a new aftermarket tach set that drives off the alternator - probably around $300-400 or so.
I will send you a couple of schematics so you can see what I mean.