Are these trips actually operated by BD? If not won't the operating carrier determine mileage earning? So you could book a BD Z fare on United Metal and get miles because the flight is operated by United.
Notice this exception noted below BD's mileage earnings on united.com:
"If you purchase a ticket on a flight that is marketed by bmi but operated by another airline (known as a code-share flight), the operating airline determines how many miles you earn for your flight. "
Someone please correct me if I'm wrong on this.