904 selective thrust washer race?

Hey everybody
I'm on the final assembly side of rebuilding a 904
My question is this transmission was missing the cupped race for the selective washer between the input and output shafts.
I got one yesterday but I want to make sure I'm installing it correctly.

Does it cup over the washer
Or cup over the input shaft?
I using tom hands rebuild book but it doesn't say anything about it..
Thank you. Mike