Now that it's become the No. 1 daytime destination for female teens, NBC's supernatural soap ''Passions'' has set its sights on another hard-to-reach audience: African-American women. ''Passions'' is tied with NBC's ''Days of Our Lives'' as the least-watched sudser in that demographic (CBS' ''Young and the Restless,'' in comparison, is No. 1), a trend NBC is trying to reverse, in part by casting syndicated R&B DJ Tom Joyner in a five-episode arc in March. He'll play a disgruntled Crane Industries employee who wreaks havoc on the firm. ''African-American households represent a disproportionately large share of the daytime audience,'' says NBC's head of daytime, Sheraton Kalouria. ''But quite frankly, many of them aren't aware 'Passions' is even on.'' Well, they'd come around a lot quicker if the smoldering Shemar Moore (the Y&R alum last seen on The WB's canceled ''Birds of Prey'') joined the show as a sexy warlock.