Update the WF container element of type structure from custom Program

Hi ,

I have one requirement, where I need to WF update container element of type structure from custom program.

Here Workflow is already triggered. I am using SAP_WAPI_CHANGE_CONTAINER.

My doubt is that, if I want update only 2 components of  in WF contaner element(type structure), how can I refer individual components.

Can you please help me on this ASAP...thanks

Regards,

Santosh,