XJ750X help with luggage solution

Hello everyone.
Yesterday I bought XJ750x 1987 after 3 months search (I missed one in June). The bike is great, better then expected, but I have a problem with luggage. I owned a Honda CM125 previously and got used on Givi 46 litre case. Now I have no idea how to mount it to my Maxim.
I know that it is not common to place a case on this bike, but I'm using it as a car alternative and having a case is realy not matter of fashion.
I do not want to remove the sissy bar or make any permanent change on the bike, since it is almost 100% original.

Any ideas are welcome and appreciated, and images of existing solutions would be great.

Thanks

 

Depending on how much space you need you can look at tail bags. They sit on the passenger seat. Here is one from Viking. I have one that is smaller that I used for a rain suit, cap, etc. Google motorcycle tail bag and you will see a lot of options.
https://www.vikingbags.com/sport-bl...LSp58Qw4KG97eYyEimdsAbGZvDt5SC-0aAuJJEALw_wcB

 

Thanks, but I need passenger seat either for my wife or my kid , so in my case that does not work.
Thank you anyway.