iNik, sorry we missed this the first time through, but we got a customer email asking for something along these lines today. That led us back to this thread and also led us to discover Don Southard's
OmniFocusCLI, which may save you some work. It's a shell script that creates OmniFocus tasks and can be used with Alfred, Hazel, etc.
(The intended use of the URL handler is pretty narrow - it's meant to pass the necessary information when there's no other way to do so than as a URL. We'd recommend using it as an input to the other automation methods that let you control OmniFocus' behavior.)