I want to use WEEK as the base member of BPC TIME dimension

Dear all experts

I want to use week as the base member of BPC 10.1  TIME dimension.

I wanna set up a account period(1 year )  by 52  week the base member.

For example: 2015.week1, 2015.week2.....

For the PERIOD property, there are only 12 values(JAN~DEC), how should I define the PERIOD property

for each week member?

Regads