BW QA System Refresh

Dear All

I would like to refresh my BW QA System with the latest BW PRD System.

Basically I want the same data of the production to be in QA system.

My challenging is to do copy and attach method from PRD to QA (copying the DB files: *.ndf and *.ldf).

But my QA is configured with different DB Name and different schema name.

SAP SID is also different.

Can somebody guide me with step by step procedure to do the copy and attach method  from BW PRDto BW QA.

System Details:

Production System

DB Name: B12

Schema Name:B12

QA System:

DB Name: B11

schema name:B11

Thanks in Advance

Sel