RCP update site for multiple platforms

I've got an RCP application built for several platforms. The target with delta pack is set OK, Product Export Wizard works OK, PDE ant build works OK. But the Update Site project creates the updates only for the single platform - the one I use for development a开发者_如何学Cctually (win32). I expect the update site to include all the dependencies from all platforms required by the listed features.. Any ideas what could go wrong and where to look?

you should take a look at tycho.
it is a mavne plugin that can generates headless product and update-sites
tycho is a eclipse project by now