We really need more in order to understand your issue. Andy is correct in saying that the modifications you make to your include and exclude lists will not show up in the backup selections portion of the policy.
If what you mean by "while backup(taking /)" is that while backing up your UNIX machines the backup job is still backing up /. Then this is what it should be doing unless you've added / to the exclude list.
Keep in mind that the include list is only needed to specify things will not be backed up because of inclusions in your exclude list. For example, if you do not want to backup a directory but you do want a single file within that directory, you would add the directory to the exclude list and then add the file you do want backed up to the include list.
I'm still not sure about the details of your problem but you may want to look over your approach. The reason I say this is that the include/exclude lists are not meant to completely modify your backup selections. They are meant to make minor changes between clients that are mostly similar in their backup selections needs.
If you are trying to setup a single policy for all UNIX clients that have vastly different backup needs by specifying / in the backup selections list, and then adding long detailed lists to the include and exclude list files you may want to consider splitting these clients into multiple policies.
