Blanket Release-default excnage rate

Dear All,

In the Blanket release distribution, exchange rate defaulted to BPA date. I been through metalink there is a ER logged for this to be defaulted to

blanket release creation date, meanwhile, we have a requirement to be the document creation date.

i have tried to do that through form personalize  as following:

On (When-NEW-Block-Instance) trigger for  po_distribution block set initial-val for po_distribution.rate_date to be sysdate .

the rate date has been successful changed to the  needed date but the rate field didn't reflect the corresponding date rate.

anybody have an idea?

Thank you