More on this. I just noticed if I simply drag a source cpp file from nautilus right into project tree in Momentics that 
works for existing files! The problem is my project has hundreds and hundreds of files all arranged into a nice and 
clean folder structure on a disk. So I though I can do the same thing I usually do in Eclipse in such situations. I just
 use [Project]->Import->General->FileSystem, point it to the directory I want to include, select subdirs/files I want to
 include into project, give it a local Project Browser path and thats it. The whole selected tree is included into my 
project preserving directory hierarchy.

I just tried, this method seems to still work in Momentics if I go with New -> Project -> C/C++ Project. 

However if I go with New -> QNX C++ Project this method doesn't work. The source tree gets included into project but 
excluded from the build.  I'm just getting

make[2]: Nothing to be done for `all'.   

Obviously I don't wont to drag almost half a thousand of C++ files manually from Nautilus. They will all end up on one 
level in Project Explorer in Momentics. There is no chance I can quickly find anything I want in there then. So I would 
like to preserve the original directory structure on disk in Project Explorer too. Just like I can do with C/C++ project
 ...        

Any ideas how to fix this?

Thanks.