I know that using the expression :”I look forward to doing business with you ” is right. How and where can I find information about using “to doing” to students?
On our web site take at look at www.englishplus.com/grammar/00000335.htm or look up “Gerund” in the Grammar Slammer glossary. “To doing business with you” is a prepositional phrase. The object of the preposition is the gerund phrase “doing business with you.”
I hope this helps.