Multi-project using custom-named main build-file

I’m developing a multi-project with a custom-named main build script file, but the subprojects are not found when calling to it.
Is this the expected behaviour?
I’ve created a repo showing the issue at https://github.com/lucasvc/gradle-multi-project-custom-buildfilename.

Thanks!

I faced with same issue. And after few hour research I found next solution:
add in your settings.gradle rootProject.buildFileName='custom-name.gradle' and launch your build

P.S. Am I late? =)