Deleting IMAP articles and having them moved to the Trash

[levander]

Here's my select method for accessing my IMAP account:

(setq gnus-secondary-select-methods
      '((nnimap "levander@mindspring"
                (nnimap-address "highhat.net"))))

To get it so that I can just hit a button that represents "deletion"
and have them moved to the Trash folder is to set point on the nnimap
+levander@mindspring:INBOX group, hit "G c", go to the bottom, and add
a new variable called nnmail-expiry-target with the value of "nnimap
+levander@mindspring:Trash" - and I do use the quotes in the text
field where the value is set.

So, I open up the nnimap+levander@mindspring:INBOX group and hit 'E'
on an article.  I hit 'B e' to run the expiry process, and the article
just stays in the Summary buffer, with a big E next to it.  In my
other mail client, Thunderbird, the mail message is still in the INBOX
folder.

I restart gnus, change the value of nnmail-expiry-target to
"levander@mindspring.com", restart a few more times, expire other
articles.  Nothing works.  I think I'm just going about this the wrong
way.

I don't care if I use the expiry feature or not.  How do I set it up
so that when I delete messages they get moved to the Trash folder?

The main reason I need it this way is that I use other mail clients
than Gnus.  If it's not consistent where deleted articles go, I'm
going to have to delete the same articles for each mail client I use
that does it a different way.

This functionality has to be on a per-group basis because I have
multiple email accounts.