Populate Time Characteristic

Experts,

I have the date in this format - 2007M01D12 in my flat file. I have to populate this to both 0Calday (YYYYMMDD) and 0Calmonth (YYYYMM) in my DSO. I am using BI 3.x. Where and How do I make these necessary changes? Please explain in detail.

Thanks,

Pooja