Why do Launchpad act differently with 64 and 32bit packages?

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http://askubuntu.com – I'm making Ubuntu packages from source code of a geology program. I can make debs on my pc and also Launchpad is able to make binary packages for 32-bit OS. I noticed an strange behavior of Launchpad. It makes both development (libfoo-dev) and shared library (libfoo) from uploaded source code for i386 though makes only binary package for amd64 from same code. Looking at i386 and amd64 buildlogs I found that for amd64 debian/rules binary-arch is called instead of debian/rules binay. This cause my source not to generate development package for amd64. How can I solve this issue? Build logs ans (HowTos)