Exchange 2010 and Exchange ActiveSync

I have been asked to set-up a test Exchange Server 2010 machine in order to test the Exchange ActiveSync system as an alternative to our existing Blackberry mobile email solution. We intend on using Windows 7 phones to hook into our Exchange system.

I have installed the server and installed a commercial SSL certificate. I have migrated a single mailbox across to the new server. I can access that mailbox quite happily in OWA and in desktop Outlook , all seems fine from that front.

I have a problem with the Exchange ActiveSync element though.

No matter what settings I use I cannot get the mobile phone to sync with the server.

The error I am getting is:

You'll need a personal certificate to connect to mail.example.co.uk. Error code 85030027

Now, my limited understanding^[1] of our set up is that we should not need personal certificates. The Exchange ActiveSync system is set to use Basic Authentication which should just be a plaintext username/password combination over SSL.

We've never needed to use Exchange ActiveSync before, so I haven't done any further set up other then accept the defaults. The handset is on our own internet wifi network so we should not need to worry about ensuring we can SSL traffic forwarded from the external IP to the internal machine at this point.

For reference I can access the OWA page under SSL and the certificate looks ok. If I manually visit the full path specified as the Exchange ActiveSync URL then I get a username and password popup box which I understand to be normal.

I feel like I'm missing something silly and would really appreciate a point in the right direction.

^[1] We have a fairly basic use for our existing Exchange Server 2003, we do not do anything complicated with it so have never needed to set up external connections or integration with mobiles before. There is probably some piece of 'common' knowledge I am lacking.