LO Draw supports import of VSD/VST files, but on windows it's not associated automagically by installer. Modification of the MSI could improve user experience.
Andras Timar committed a patch related to this issue. It has been pushed to "libreoffice-3-6": http://cgit.freedesktop.org/libreoffice/core/commit/?id=0e6c53a535758ef62110a8744b600633e564af03&g=libreoffice-3-6 fdo#51274 optionally associate Visio file types (vsd/vst) to Draw It will be available in LibreOffice 3.6.
Andras Timar committed a patch related to this issue. It has been pushed to "master": http://cgit.freedesktop.org/libreoffice/core/commit/?id=ade85a43e1369cb9e0026f048ed410a964db48d9 fdo#51274 optionally associate Visio file types (vsd/vst) to Draw
It was mainly a copy&paste job, it will work as good or as bad as the file association for other MSO file types. There are a few issues reported in Bugzilla. Anyway, this bug has been resolved.