I read their documentation and understand the modifications needed. However, do I install the same code for both and then do the modifications ? or do I install two separate analytics codes and then apply the modifications ?
Firstly if you want to track the visitors form the mini sites into the main one including the conversion they get you … there is not requirement of putting the same code on all sites. You can see conversion from source information via the referral reports in the main site GA profile.
however if you still insist then you should put the SAME code modified code on all the minisites… to clarify this would mean that all the codes on all sites will have the same _gat._getTracker(“UA-xxxxxx-x”) value.