source files not in current directory

[Alex Hornby]

I'm using CVS automake and have source files in sub directories of my
project like so:

./forward_idl/Foo/Bar.cpp

In my Makefile.am I list them 

fooserver_SOURCES = forward_idl/Foo/Bar.cpp

In the generated Makefile I see

fooserver_OBJECTS = Bar_c.o 
Bar_c.o: forward_idl/Foo/Bar_c.cpp

That would be fine, but AFAICT there is no way for make to apply the
normal .c.o suffix rule in this case to produce the object file.  How
can I get this behaviour?

TIA
Alex.