Hi Manuel,
so following the central approach you would need some server functionality that
1. takes username@domain.com and
2. stripes the @domain.com
One add. question to that. Do you have the SAP Username available as AD field by chance? I know of customers using sapUserName as LDAP attribute.
Of course there's still the option with the report in the AS ABAP (better would be the RSUSREXTID BADI). But I assume having a central solution would be better.
Now we could argue that for the old systems you need to have a usrextid mapping anyhow. But if this mapping would be consitently you could make use of standard RSUSREXT without having the necessity to code.
So I think we already have solution. But a central solution is better. Let me think a little bit about how to achieve a central mapping.
Regards,
Mathias