Vista - Message Store Location Change

I have used OE for many years. I have receive a large amounts of email. In OE
I have learned tricks in storing and transferring mail that would make some
tech support guys cringe. I have spoke to a few. These tricks do not work for
Vista.

I am concerned about a the message about changing the file store location. I
tried to move the file store to a temp location. I wish to offload a chunk of
mail to an external hard drive. I receive the message that the new folder is
not empty.
This concerns me greatly. I wish to have multiple store locations on
different hard drives. Each has a different mail use. What I am seeing is
that once I reset the store location, I can not reset it back at a latter
time. I simply recieve a message that store location is not empty and I am
not able to continue. I do understand about the option to export and import
files and might consider this. However, I should be able to have several
store directories and be able to switch between them as needed. In OE, this
wasn't a problem. In Windows Mail, I am not seeing how to do this. The mail
program should be able to return to a store location is was at orginally.
With is message stopping me, I do not see this as being possible. I have
hundreds of thousands of messages. Multiple stores on seperate drives is the
most practical solution.

Thomas Cornell