Wow, choosing a target that depends on a digitally signed license is probably the most sophisticated way to start rce'ing
I guess the best way to break its protection would be to generate your own public/private key pair using MS' CSP and replace the public key BLOB inside the exe (resource id 163) with your own one.
Use the private key to code a simple keygen (you'll also need it to RE the license file format - but from what I saw the format isn't too complicated)
The main advantage of this approach is that you can crack future versions by just replacing its BLOB resource with your own one.
You'll quickly find the license handler if you look for references to CryptAcquireContextW, CryptImportKey and CryptDecrypt.