Hey Moongold,
The buttons from the WiiMote actually are available, but they are treated more like keys on the keyboard - they don't show up in the list of data-sources (there would too many options to list them all at once), but you can assign them just the same.
What that means is that you assign them using the "detect button" option that shows up when you right+click on a vvbutton.
As for your question about OSCulator, I'm not at all familiar with the program so I don't think I can be of much use for that. I don't really understand what you are trying to describe at all. What are the x and y values coming in over MIDI? What do you mean be a mouse-like movement?
- David @ VV