[Dovecot] mbox vs maildir

Ignoring my previous message just for a second, I realized that my 

config wasn't correct. So I have this for namespaces:

namespace private { separator = / prefix = "mail/" location = mbox:~/mail:INBOX=/var/mail/%u inbox = yes hidden = no list = yes # for v1.1+ }

namespace private { separator = / prefix = "mail-Archives/" location = maildir:~/mail-Archives:LAYOUT=fs inbox = no hidden = no list = yes subscriptions = yes }

But when I'm in Thunderbird and I try to subscribe to anything that 

falls inside of ~/mail-Archives/ it won't work. I can browser all the way down to the folder, but I can't see anything within that folder.

For example, consider the full path to the following 'Ashley-09' 

mailbox:

~/mail-Archives/2009/Ashley/Ashley-Jan09

In Thunderbird, when I hit 'Subscribe' I can browse down to '2009' 

and I can see 'Ashley', but I can't drill down into it and subscribe to 'Ashley-Jan09'.

What am I missing here?