coding in workflow

Hi ,

I want to send notification to cost center responsible person when ever PR is created with type 'K' . i am able to extract cost center which comes with business object BUS2105 but finally i am not able to find responsible person ID for that cost center. because i dont how to code this and exactly where to code , so that i can extract responsible person id when i pass that cost center.

please advice me on this.

Thanks,

rahul