how to build project with locally compiled phobos

[Mengu]

hi all

i've successfully compiled phobos master with gmake on freebsd. 
(make fails, i've no clue at all as to why)

how do i compile my project now against my local phobos with dub? 
with plain dmd?

i tried (in dub.sdl):
- full path to new libphobos.so with -defaultlib to dflags
- full path to new libphobos.so to lflags

i checked with ldd and saw the original libphobos.so was used. my 
current workaround is copying mine to /usr/lib.

thanks in advanced.