You should have the Microsoft Exchange Server administrator to enable Autodiscover in Outlook Web Access for the time it takes you to first authenticate your Mail program on your iPad. Afterwards the administrator can disable Auto-Discovery if it is deemed undesirable.
Apple's documentation for connecting to a Macintosh says the following. I'm assuming the same will apply to configuring the Mail app on an iPad.
Connecting to an Exchange Server
To connect a Mac to an Exchange server, you’ll need the following
pieces of information from the server administrator:
The fully qualified domain name for the organization’s Client
Access Server (CAS), typically expressed in the format:
The Exchange user name, which is generated by the administrator for
each individual user.
The Exchange password, which is also generated for each user. Once
you have the required information, you can either manually configure
your Mac to use Exchange, or configure the Mac using the Exchange
Autodiscover service, if it’s enabled.
Connect to an Exchange server with Autodiscover enabled:
The easiest way to set up Mail, Address Book, and iCal to access
Exchange is the Exchange Autodiscover service. If this feature is
enabled on the Exchange Server, simply open the Add Account pane in
Mail on your Mac and enter your Exchange email address and password.
Mail uses the Autodiscover service in Exchange to obtain the relevant
information and you can start using Exchange services immediately.