paymet terms not copying in PO

Hi Expertise,

I mantain a paymet terms in vendor master, for example

payment terms - Z001.

While creating a standard PO (NB), the payment terms get copyed from from vendor master data & showing in delivery/invoice tab as

payment terms - Z001

Payment in - 14 days 4%

payment in - 30 days 2 % .

While entering the envoice by MIRO it showing the same in the payment tab. It show

payment terms - Z001

Payment in - 14 days 4%

payment in - 30 days 2 % in the payment tab.

But after saving the invoice when I disply the invoice document in MIR4 it not showing the payment terms. It only show the condition ie the discount get in no of days. It show

payment terms - (Blank)

Payment in - 14 days 4%

payment in - 30 days 2 % .

Can any one help me to solve the above issue.

Thanks in advance.

Regards,

s p sahu