How to mount seat to original hinges?

[68riviera430]

I want to put a bum stop seat on my bike but be able to switch it back and forth from that to the original seat for passenger riding as well. has anyone done it or Does anyone have any mounting ideas that allow for quick switching back and forth between seats? I particualrly am looking at a roccity seat. For a 75cb550f by the way

 

[JDrawdy]

I bought an abs seat pan. When I received it it had some instructions for using the stock metal pan to save the hinges. If nobody answers it better, then I will pull them out when I get home from work and post em for you.
It seems it takes some reshaping of the stock pan, naturally.

 

[Steve Zodiak]

You can check out how I did it on my Guzzi seat...

http://www.dotheton.com/forum/index.php?topic=18525.0

Steve