The founder of Long & Foster, the Washington region's largest residential real estate brokerage, struck a nerve last week when he urged his thousands of agents to recommend the company's in-house mortgage lender more often and stop working with outside lenders such as Bank of America.In an e-mail to all Long & Foster agents and managers, P. Wesley Foster Jr. chastised his workers for funding mortgages through Bank of America more than 2,200 times last year and through Wells Fargo instead of using Long & Foster's affiliate, Prosperity Mortgage. This comes at a time when home sales have slowed significantly.