I think I'm a tad confused. In my experience you don't need to download any apps to get Android to connect to an Exchange server. Once the account is added, it just brings everything into the respective included apps.

Then again, I've only done this on a few phones, but each time I'm pretty sure we didn't need to do anything else to get email, calendar, and contacts into the phone (I'm not sure what else you'd need, either).

What are you experiencing when you try to connect?