New ur22 w/ LE 7 does not operate w/ os 10.5.8 as stated?

Requirements showed os 10.5.8 is compatible, but when I launched the software it actually requires os 10.6.

I can not unfortunately install 10.6 snow leopard because my g5 isn’t intel it’s PowerPC.

Can I be provided with a link from steinberg to run cubase 6.5?
(If that is even a compatible version) and still use the newly purchased ur22?

Thanks for the consideration

Mac 10.5.8 dual PowerPC G5 2 g