Please, read this old thread - looks like this problem still is not solved
>>The primary key as foreign key limitation is from the 2.0 manual. You are using 2.1 with symfony, which supports this. Please use the correct manual.
>> The only problem is that the reverse engineering does not support this. You have to reverse engineer yourself, or write a patch to have Doctrine support this. I would really appreciate it
As I understand it is supported in the "core", but some reverse engineer script is still not using that possibility.
Could you at least point where this can fixed?