The procedure for setting up multiple email accounts under one profile is as bellow: (note it should work with your suggested setup, i know it does with other types of accounts)
first off set up your mail profile if you haven’t already done so and configure your exchange account
once the exchange account is setup and working you are going to go to:
Tools –> Account settings
here you are going to go to the <b>data files</b> tab and add a new one name it whatever you want but preferably something descriptive as to the account it will hold mail for.
once you completed the add wizard there should be a new data file location listed now go to the <b>E-Mail</b> tab and click on new complete the wizard for your pop3 account.
Once the account is listed in the tab select it and change the mail delivery location for it by clicking the <i>change folder</i> button located in the same form.
make sure that you select the new data file that you created earlier for the mail to be delivered to. and that is it.. one thing to remeMber is that the default mail account listed here is where the emails that are generated on this profile will come from.
Hope it helps