I was having this same problem here is what you have to do.
THe redirector Will not allow you to open attachments. (stupid I Know)
Go to:
http://www.discoverblackberry.com/pe...internet.shtml
at the bottom of the page select your carrier ie verizion cingular etc.
Select New Account
On your BB go to Options, Status to get your Pin and ESN number
Set up a blackberry account.
ask your IT person (or create the filters yourself) to have your mail forwarded to the account you have created with blackberry.
Now you will get your attachments. Oh and delete the redirector once this is done otherwise you will get duplicate messages.
Hope this helps!
~ Hope