Christian - I created a Generic MIDI Control for Cubase and Nuendo, and have created a thread in the general tips and tricks forum (before this one was created). If you don't have a controller that will send all of the MIDI streams, you of course can draw them in or use a MIDI loopback device and the generic control on a separate track to create the data.
As far as creating good brass arrangements - listen to good brass tunes and imitate them. It's just like learning to play an instrument - you have to listen and imitate before you can internalize and make it your own. Good luck.