SAN ANTONIO — Buchanan Street Partners has negotiated a $20.4 million financing package for the development of Stone Oak Centre, an 81,560-square-foot office and retail property in San Antonio. The project, which is located along Stone Oak Parkway, includes five Class A, two-story office buildings and two retail buildings. Buchanan Street Partners structured a $15.5 million construction loan and arranged $4.92 million in equity with third-party investor Ascent Real Estate Advisors. The financing was arranged on behalf of the developer, M.S. Walker & Associates. Construction is slated to begin this summer on Stone Oak Centre, which is expected to be fully leased by January 2009.