Restrict certain Doc. Types in Purchase Req. ME53N

Hi All,

My requirement is to restrict display of document types with descriptions "Do Not Use" in the ME53N drop down list .

I know we can have authorization object " M_BANF_BSA " but this will not allow user to select Doc types and these doc types will appear in drop dawn.

Is there any way to filter out doc types from appearing in ME53N drop dawn list for document types.

I tried with implicit enhancement where I delete the Doc type  details if they contain pattern "Do Not Use" after selecting from T161T but it's still appearing

in drop down.

Does anybody know how to achieve this..

Regard,

Sachin