How can I carry out new pricing from info record when I adopt from old PO in ME21N.

How can I carry out new pricing from info record when I adopt from old PO in ME21N.

When I use the adopt botton to copy item from old PO to new PO, I hope the system can calcuate the material's value automaticly.

I try to use BADI ME_DEFINE_CALCTYPE->DEFINE_CALCTYPE, and change the CH_X_LF_CALCTYPE to 'B', but only when I change the item, the value for material can be calcuate automaticly. If I only adopt the old item, it can't be calcaute automaticly.

Can any one know how can I do it?

PS:
  About details, please refer to the attachment.

Thanks.