Why is that not solving the problem, if they do URC, they should be able to upload/download the remote data to their program and go from there.
However, it might not be worth it to them, but on the other hand, if you have a decent system, then you probably should be looking for a new Custom Installer to maintain your system. It may take some time looking, but it is an important step. I am really sorry that your custom installer closed shop.
URC's software policy is that the dealer you bought the remotes from has the choice to share the software or not. URC will not give you the software. They do that so when you have problems programming, you have to call the dealer for help, and not bog down tech support so when the CI's call we're not on hold for 45min while on the jobsite.
Since your dealer went under, keep trying other local dealers until you get one that may help. I know it's not what you wanted, but that's how it is. Just keep trying you'l find one. You may need to buy "something" but it's a small price to pay to get the software for future use.