dssi-vst in Debian is explicitely linked to
wine, while the unstable repositories contains the (much better)
wine-unstable packages.
Here is a version of dssi-vst relinked with wine-unstable. In fact you can even use the
on-the-edge wine-unstable packages, then!
deb http://jeandamiendurand.free.fr/debian/dssi-vst sid main
deb-src http://jeandamiendurand.free.fr/debian/dssi-vst sid main