Adding exchange account to Outlook with pop3 account

Hi,

My company is in the process of merging with another company. We are
running an Exchange Server (SBS 2003) and they are using pop3 accounts.
These will become remote users for us, from a networking perspective, and I
have set up all of our existing remote users to use "Outlook over the
internet" for Outlook 2003.
Can I add an Exchange e-mail account to their Outlook, set it up for
"Outlook over the internet" and leave their existing pop3 account active as
well, and that way they will receive corporate e-mail along with their
webmail?
Eventually after the merger is complete and they have transitioned all of
their clients over to their new e-mail address with our company, I will be
able to get rid of the pop3 account.

Any advice?

Mike