Hey @letrastudio,
I’m afraid that what you’re hoping to do won’t be easily possible You can see a related question here: Redirects that are not case sensitive - #14 by jen
We normalize URLs so you don’t get an SEO penalty for having the same content at two different paths, but I understand this is getting in the way of what you want to do in this case.
A weird thing you could try is putting a redirect in the mix, as I’m not sure we normalize redirected-to paths. This would mean your site structure would be something like this:
# project root
1lm6vm
/id/
|- 1LM6VM.html
and you could have a redirect rule like:
/1lm6vm /id/1LM6VM 301!
If this works, you would have to create a redirect rule for each ID… so definitely not ideal, but worth a try if the uppercase piece is really critical.