I have this all working with the following setup.
I have 2 Filters set up in my gmail. They are as follows:
1) Matches: from:(XXXXX@gmail.com) in:inbox Do this: Skip Inbox
2) Matches: in:inbox Do this: Forward to
Then I have a auto BCC to my gmail(XXXX@gmail.com) for all outgoing mail from my BB.
With this setup all my inbox mail makes it to my blackberry and when i respond from the blackberry it shows up in gmail as sent mail.