Hi Free, hi Javier,
I don't feel very confident as far as legal matters are concerned, but maybe Daniel James, who has already dealt with other audio/multimedia related legal issues may help us
I believe the only long-term solution is for Steinberg to release the headers under a free software compatible licence. I don't think this is impossible now, for several reasons...
1. Steinberg is now owned by Yamaha, a hardware company 2. Yamaha is actively funding Linux-related audio development, for mLAN3. There are a significant number of commercial audio products now based on Linux kernels, with more likely to come
So I think it would be in Steinberg's interest to solve the licence problem (given that it will want to maintain the hegemony of the VST format). I believe this is something that the linuxaudio.org consortium should look at.
Cheers! Daniel