Your DSN is OK: manual sql is successfull.
it seems to me that you can adapt your problem :
If you type in manual sql select * from … then clic on the button to show the graphic assistant, does MSQuery shows the file fields ? if yes, you have force msquery to help you
other way : in one of your *USRLIBL, create a VIEW that contains your shortcut :
create view mylib/myshortcut as select * from qusrsys/…
last but not least : there is some ways to declare the library list in the DSN (yes, a list, not only one lib), and depending on where is the first comma, search rules in the server are changed.
Drag the net for details, I have not now a 400 under hand