You can politely ask your IT Admin if they would mind editing your Exchange Profile settings. Just let them know what your objective is, and ask them to Forward ALL Incoming Messages To:
. Make sure to ask that they click the box "Leave a copy of messages on the server". This will push all of your work email to the device, but still allow you to work with your Outlook/Email program at your desk.
Not sure if this was the solution you were looking for, but this would give you your Corporate emails and your BIS emails on the device. Just make sure to remove the corporate email you setup on BIS (if they do forward it for you) and keep only your
on the page, with the Reply-To address as whichever address you want people to Reply To.
Confusing? Yes. Worth it? Probably. :P