I think there is actually an easier way to make palladium prints in silver paper. I had a discussion with Sandy about tonning Kallitypes with a pd solution, and how the pd does replace the silver in the print.
If my theory holds true, I think you can wash the silver print and BEFORE you fix it, you can tone it with a pd solution and essentially get a pd print in silver paper. I will be making this experiment this weekend and let you all know. BTW seems the same mechanism will apply for pt.