PO TAx Condition with different rates in various items in single PO

Dear SAp Gurus

we have created single PO with 10 nos line items.

for 3 items ZCST is 12.5 %

rest items ZCST is 14.5 %

but in PO showing only ZCST 14.5 % with BAsic Price etc.. not calculating / Showing ZCST 12.5 % in the PO..

how can we solve this please advice

Regards,

Rajesh G