This is definitely a limitation of the trial installation. A trial doesn't grant you full usage of the application. Yes, you can use and install it, but certain features will be limited, just like the case you're experiencing. The only way to overcome this is by purchasing the full version from its official developer, then you can use it to send the number of lines you need.
Use the following contact details to get in touch with the developer:
Tel: +45 45 85 60 50
Fax: +45 45 85 60 53