debian wheezy multiarch support allows installation of i386 packages to amd64 host provided that there is i386 version of libraries used by the package.
is there any advantage of amd64 kamailio versus i386 one? how does kamailio benefit from 64 bit architecture or does it not?
if not, the on wheezy amd64 packages would not be needed. this is what e.g. google has done with chrome browser packages.
i have noticed that amd64 version of kamailio requires quite a lot more memory than i386 version, which it not necessarily a good thing.
-- juha