[SOS] glade version contradicts to gtk+ version

[nowheremansq]

Hello all:
I found a problem yesterday when I tried to work on a gtk+ project with glade IDE:
As we know, the version of gtk+ in the newest portage is 2.20. Of course , my version is 2.20.Whereas, the version of glade is 3.6.7. Actually, You may found the official documents of glade 3.6.7 says:" This release will make everything horizontally oriented in any project created prior to GTK+ 2.16." (http://mail.gnome.org/archives/gnome-announce-list/2009-June/msg00063.html).
So, It seems that glade version contradicts to gtk+ version! How could I use glade?
p.s.:When I open the glade. It just let me choose a version of gtk+ from 2.8 2.10 2.12 2.14 2.16. After I choose the newest one, 2.16 .It just say"Project has no deprecated widgets or version mismatches".
Actually, glade 3.7 which support gtk+2.20 has released, but I cannot get it with portage.
What is the best way to work out this problem?? (Please don't just tell me download the source code from gnome and compile it. you know, I just wanna use portage to manage every software )
THX~~~~