[Qt-creator] How to set Shadow Build path in the project(*.por) file?

[rcyboom]

Hello,
everyone:
I can set the  path of output files in the .pro file,which is using:

DESTDIR = ../../bin

I down't know how to setting the shadow build path except in the UI interface of Qt creator,can you help me?
Because I has many projects in a root path.
I want that is a clean directory just contain source and config files.
win7 64bit Home+Qt 4.8 lib for vs+Qt creator 2.4.82
Thanks!