Php Site Registration Decoder?

I own a legal copy of a php script. I purchased it a few years ago and wanted to switch the software to a new domain. However, I discovered that the script is registered to a specific domain. In order for the script to run it requires the code and the code will only run from the registered domain.

I have no plans to install it on multiple sites. That defeats the purpose of the software which is to centralize activities on the site. I contacted their support but they were not helpful. They tell me that the script creates it's own code and they don't have a database of codes. Therefore they can't re-issue another key so I can move the script to a new domain.

Anyone have some ideas of how I might decrypt the code? It looks like it's about 25 characters long. Hate to have to pay for it again. Seems they should have a better system. I understand protecting your scripts but you'd think they would have some way to re-issue the keys.

This looks like a rather simple registration key. I just need a way to decrypt it or re-issue the key to my other domain.

Any ideas?

Thanks!