Wrong answer in one of the quizzes on this website?

[Sir Sanderson]

Hey
I've been doing a few of the quizzes on your page in order to raise my English to proficiency level and in my oppinion there is a wrong answer in one of the advanced quizzes (the "Gerund/Infinitive" one with 69 questions).
Q5 - It was Paul; I saw him ........ it
1. to do
2. doing
According to the answer sheet, "I saw him to do it" is correct. I, on the contrary, think this complete rubbish. I have never seen a collocation of the verb "see" and the structure "to + infinitive". I can be mistaken, of course, so which answer is correct???

[Tdol]

Thanks for spotting that, Sir S, it has duly been derubbished..