For BADI in MM02 for checking material based on characteristics value

Hi all,

i have a requirement to use a badi for MM02 txn.

Actually my requirement is that any material having atinn value "0000000076"

should not be used to create sales order if the value associated with its atwrt = 'h'.

(there are two atwrt values for atinn76, which are 'h' and 'f').

Now for this i am using BADI....

BADI_MATERIAL_CHECK

BADI_MAT_F_SPEC_SEL

BADI_MATERIAL_REF

Please tell me which badi will be useful for that, and if there is any other

good approach, then also, please tell me.