Cannot "Send As" different user in Outlook 2007 ?

[albertwt]

Hi,

I wonder why I am still unable to "send as" from my Outlook using this particular mailbox ? eventhough:

1. I was able to open up the Mailbox successfully as additional mailbox in my Outlook

2. Grant my self "FULL ACCESS" and the "Send on Behalf"

do I have to make this mailbox as "Shared mailbox" instead of normal user mailbox ?

Any help would be greatly appreciated.

Thanks.