This "hack" did work for P6 (see -> http://www.keindesign.de/stefan/poser/3gb.html), the trickier bit is adding the /3GB flag to boot.ini

Essentially what you need to do is looks at the "Peak Memory Consumption" using the Task Manager, and generate a very large scene.
If you see a value of over 2GB then it's basically working.
Problems may not appear until you whatever your doing hits the code that chokes.