CHICAGO--(BUSINESS WIRE)--Fitch Ratings has upgraded three classes and affirmed the remaining classes of Wachovia Bank Commercial Mortgage Trust (WBCMT) series 2005-C20 commercial mortgage pass-through certificates. A detailed list of rating actions follows at the end of this release KEY RATING DRIVERS The upgrades reflect an increase in credit enhancement and expectation of future paydown due to upcoming loan maturities and the stable performance of the underlying collateral pool. Fitch modell