Unfortunately, this has proven to be the most difficult, shaky, and obscure part of the WPS. The WPS is extremely multithreaded, and IBM hasn't cared to document exactly those interfaces which control the various file threads.
There are a few things which I have found anyway, even though IBM didn't
want me to, so here we go.
Note: As usual, all file operation enhancements are disabled per
default in order to avoid confusion. Go to the "Features" page in the
"&xwp; Setup" object and check the
flags in the "File operations" tree to enable the various features.