CMS OpenX php change

Hi, We are looking for someone who can help us with our OpenX server. This job is a small puzzle but we need you to make new functionalities in the near future also. Our developer, who is no longer with us, somehow managed to give a single user different menu buttons. This is great since we would like to customise the buttons per user we create in OpenX. Most likely he has achieved this via editing some of the php files, but we do not know which. Your help on which files to look at would be appreciated. The individual who can do this preferably has experience with CMS kind off php systems so he knows that one file is linked to another... Thanks and regards, Ndroi Team