Radial velocities of main emission peaks measured for highly ionized elements (open symbols, Table 6) as a function of the photometric phase (1). Compared are radial velocity curves for the M-type (Fekel et al. 2000, solid line, filled circles) and A-type absorption lines (Mikolajewska & Kenyon 1992,dashed line, asterisks), and emission peaks of [Fe vii] λ6087 line (Iijima 1988,grey line, crosses). Systemic velocity of –117.44 km s^-1 was subtracted.