In the wake of its highly publicized acquisition of U.S. Trust Corp., Charles Schwab is fighting to convince the 6,000 plus independent financial advisers that make up its brokerage force that the purchase of U.S. Trust Corp. will not encroach on their business. The dilemma is a significant one for Schwab, whose advisers control almost a quarter of the firm's $1 trillion in assets. Chief among their concerns is that by buying U.S. Trust Corp., Schwab will hone in on the customers with assets of $250,000 to $5 million, a territory traditionally covered by the advisers. Schwab's strategy in buying U.S. Trust Corp. is to target wealthy investors, a demographic that had eluded it until recently. In September, Schwab attempted to quiet the advisers' fears during its annual investment conference. There, officials went out of their way to prove how profitable the U.S. Trust Corp. deal would be to them in the long term.