Purchase Order Workflow approve and reject actions not available on role centre

Hello,

I have set up a Purchase Order workflow and the emails include links to the PO information on Role Centre Portal. The Approve / Reject buttons on the ribbon are greyed out and the Actions button does not include the usual Approve/Reject/Change etc options. Just History and Recall.

If I log into AX I have permission to take these actions.

Is it that the Role Centre Sharepoint is not correctly inheriting my permissions?

Or does the Kernal upgrade required for email approvals also apply to approvals via the portal (Microsoft Dynamics AX 2012 R2 White Paper: Workflow Approval via Email).

We are running on AX 2012 CU3.

Thanks for your help,

Katie