Thornburg Mortgage, a small publicly traded lender specializing in boutique products for high-end borrowers, has picked a growing private-label outsourcing firm to help reach its ambitious origination goals. Thornburg wants to generate up to $2.8 billion in new mortgages this year, which would amount to a 22 percent increase over its 2002 volume of $2.3 billion. That’s an “aggressive, but not unreasonable” target, said Joseph Badal, CEO of the firm’s mortgage lending operations. “We