As you can see, nothing too special going on here. I can't for the life of me remember how I got it all set up. I'm pretty sure I had to format the device on a PC though, possibly a couple times doing a "slow" format (un-check "quick"), before it took. As you can see I used fat32, works fine, the Amiga recognizes it seamlessly. Just like any other partition or removable disk. Pop it out, the icon goes away off Workbench. Pop it back in, it shows back up.
Maybe confirm your version of l:fat95 matches mine?
Actually, you know what? I just turned around to take a couple more pictures.
You need to create a Devs/DOSDriver textfile for your device. Last two pics is what mine looks like. Struuugggling to recall, but I think this is where I had trouble - you need to create one, but where do you get the values? I think this is where I really hit a wall, none of the examples are even close to what I was trying to do, eventually just wound up going with trial-and-error guesswork for things like "Unit #" (mine is different because the cardreader has LUN's...), etc.
Hope this helps!
(set 1 of pictures)