Hi,
To add current system date in dso..Follow the below steps.
Create a characteristic infoobject of type DATS.
Add the same in Keyfields of DSO.
Now at transformation level--Double click on that object--Map any date field from source---Rule type --Formula--Edit--Choose-SYST-DATUM (Current date).Save and Activate the Transformation.
This will always give you the current date whenever your load will happen.
Hope that helps.
Regards,
AL