You should use exclude and include lists

Add your parent folder to the exclude lists and the subfolders you want to backup to include list.
As include list overrides exclude list only subfolders is backup up.

Please see the following technotes for more information

http://seer.entsupport.symantec.com/docs/277155.htm

http://seer.entsupport.symantec.com/docs/268665.htm

Anton, if he does that he won't get the files in the parent folder.

But it may be close to what you want.
But I hate making big exclude files.

do the \folder\*

exclude \folderr\sub-folder\ and folder\sub-folder-2\

then do a new stream for \folder\sub-folder\

I think this will exclude the sub folders in the stream for the parent stream, and force the backup of the sub folders because you say to back them up.

But test and verify... not 100% sure, as I just don't backup this way.
 

even if you stipulate it in the policy as a backup selection.

The only option I see would be to have 2 separate policies:

1) for the sub-folders you want to backup up entered as per the original post (without the E:\folder\* entry)

2) for the E:\folder\* as a backup selection with an exclude list of everything else (this could be a pain to administer & could well affect backup performance whilst NB determines what needs backing up)

i think this might help..

E:\folder\*.*

but it may not backup files with no extension