I'm back with another issue
I had a .p12 certificate (with public certificate and private key inside, obviously), which can not be imported directly to Progress with the certutil utility. Finally a few hours ago I could separate the p12 file in two others files; .pem public certificate and .pem private key.
Now, I have already installed the .pem public certificate into Progress with certutil -import 'cert path'. But, how can I install/import the private key so that Progress to recognize me?