How do I select multiple files from ProjectWise?

I am trying to get a list of files to process on from the user but I have not been able to figure out how to do this.  I can get one file fine via the mdlDialog_fileOpen inside the stdmdlbltin.dll, but as far as I can tell, there is no way to allow the user to select multiple files.

What I'm looking for is the dialog you get when you try to attach a reference to a file.  It has a single "tab" at the top that says Select.  Inside there, you can select multiple documents by hitting control or shift.  Or alternatively, hitting the Add button, which adds to the bottom panel.

I've tried using the mdlFileList_Edit, but that appears to allow me to open a folder, which is not what I'm looking for.

My backup plan is to use the batch processor, but I'd prefer not to do that.

Any help would be greatly appreciated.