Exchange Email Setup on Asus ME310t

Hi,
I was wondering if anyone could offer some advise.

I work as a systems administrator in a small company, late last year, some of our directors purchased iphones and ipads, I configured the server, in order for them to set up exchange accounts, and allow them to sync both internal and external to our company network. All works fine.

Someone has now come to me with an Asus tablet, requesting the very same thing, I thought this would be relatively straight forward, however, I have spent hours on this, and cannot get any success.

I eventually got past errors about opening the server connection, only now to be faced with an error of 'you don't have permission to sync with this server'.

The frustrating thing with this, is I can find no different between the user accounts in active directory, and when it came down to it, the user I am trying to setup on this tablet, sets up instantly on an iphone / ipad?!

I am out of ideas, and wondered if anyone has had similar issues, or knows the fundamental differences between the sync process of an iphone and an asus tablet?

Thanks
Heather