downloading latest source from cvs

I'm using Windows and I want to download the lastest beta source (7.4).
I read that I need to use the WIN32_DEV tag.

How do I do this if I'm using Wincvs, I know how to download from the
postgrsql cvs.

I use the following command:
cvs -z3 -d :pserver:anoncvs@anoncvs.postgresql.org:/projects/cvsroot co -P
pgsql

But how do you tell it that I only want what's tagged as WIN32_DEV?

Thanks