Setting Default Values for Standard Fields

Hi,

Can someone confirm if it is possible to set Default Values for SAP standard fields (i.e. Organisational Unit, Location or Description) in documents such as Master Agreement and Projects?

It seems possible for customised fields in the Extension Definition, but not in the Page Customisation for standard fields.

I tried using the Dimension Fields in Page Customisation, but the system ignores them.

Would I have to hide the standard fields and recreate in Extension Definition, referencing the Object Type?

Many thanks,

Mike