for anybody interested I have had a response from Autodesk Support which reads:
Thank you for choosing Autodesk Support.
You are correct that in AutoCAD Architecture 2013 this behavior has changed and we have already reported this to our development team for further research.
In AutoCAD Architecture 2012 and previous releases, the "Face" command (from the Ribbon > "View" tab > "Coordinates" panel) invoked the AECALIGNUCSTOFACE command.
Now in AutoCAD Architecture 2013 the same button calls the VIEW command, which - as a standard AutoCAD command - will not work on AEC elements.
As already mentioned, this has been reported to our development team. Development will further research on this and also assess if a product modification is necessary. Currently though I am not able to give you any further reliable information on this.
As a workaround for the moment you can invoke the AECALIGNUCSTOFACE command from the command line - or change the macro behind the ribbon button manually using the "Customize User Interface". The correct command macro should be as follows:
I hope this helps - please advice if this resolves the issue for you or in case you are in need of any further assistance.
So, there we have it - a problem and a solution, regards Aidan