Mirror Syncing Ignoring Rules?

Toucan, Toucan! I love you so, but why do you still continue to confuse me with your synchronizing ways?

I suppose the first thing to do is to clarify exactly what "Mirror" does. If understand correctly it's basically a "Copy" and "Clean" in one action, correct? So files are ALWAYS copied from the source regardless?

To explain what I'm trying to do:
I'm trying to copy my PortableApps directory from my desktop PC to my USB drive, but I want to exclude some of the larger apps like OpenOffice to use less space on my USB drive. Now, I'm working under the assumption that my desktop is the ultimate source and that any changes to apps on the flash drive should be ignored. So initially without much thought and investigation I thought that a Mirror would be what I needed.

However, after I'd set up the rules and did a preview I noticed that it was still claiming that directories like OpenOffice should be copied across. I thought perhaps the preview didn't take into account the rules, and so ran the process anyway. To my surprise, OpenOffice got copied across to my flash drive.

To create the exclusion rule, I used the method whereby you right click the directory in the source listing.

Perhaps I just am not understanding something correctly, I mean as it turns out, a Mirror isn't really what I need anyway. What I'm really after is an "Update" and "Clean" in one action, which I believe doesn't exist, also correct?

Oh well, Toucan is still great whatever the deal is!

I'm using 2.2.1 on Win XP for the record.