I went back to China several times with my H1B visa in the past several years. The first time you should go to the Embassy for interview, then later on you can just apply for your H1B visa through Zhong1xin4 Yin2hang2. I never had any problems.
BTW, I worked in a university, and I usually asked my dean to write a letter for me. I didn't go back with my H1B visa recently, so I don't know if the policy has been changed.