How to read the attributes of BOR in a delegated BOR object method?

Hi,

I had created a subobject (ZVBRK) for the standard BOR object VBRK to trigger the workflow for VF01. I am able to start the workflow which is working fine. I had created a method in BOR and a standard task to call the method. In the standard task a container element came automatically with the business object ZVBRK type as below.

Billingdoc is key for the BOR object and remaining parameters are the attributes of the object.

Inside the object method how can I read these attributes of this object instance? Should I have to create an import parameter for the method for this WI_OBJECT_ID task container attribute.

Reards,

Praveen.