Changing the Open/Save As shortcut tiles

When you open or save a file with Win2K onwards, the location box appears (where you want to either open your file from or save it to).

The standard tiles along the left are shortcuts to:
– My Recent Documents
– Desktop
– My Documents
– My Computer
– My Network Places

My question is…
How do I specify a folder for one of these tiles?
I’m sure there’s gotta be a registry hack somewhere…

Thanks!