Have you read Tracy's third book?
I think that will have all the answers you need. You are right in that basically you need to break him of the association of feeding to sleep so he can sleep on his own.
I have to warn you, it doesn't work instantly. You've probably got three or so tough nights, then another week or so of work at DS's age.
Also, read the sleep interview for some answers to lots of other questions that are common in doing PU/PD