Si IV 1393 Å component formed in material that is approaching the observer at 684 km s^-1 in the five HST spectra obtained in 1999 covering the 19.3 d binary orbital cycle. Its stability over this timescale indicates that it is formed in circumbinary material, contrary to other absorption features that undergo velocity shifts from one orbital phase to another. Orbital phases are indicated and time of observation increases downward.