OK, I did the new git setup so now submodules can track the latest master branches.Please use git >= 1.8.2 to get the new features.

To clone the lxde-qt repos as a whole:
> git clone https://github.com/lxde/lxde-qt.git
> git submodule init
> git submodule update --remote

If you already have the lxde-qt repo, do the following to update it.
> git submodule update --remote

Then you should get all of code in every submodules updated, theoratically.