Link a document to vendor master and outline agreement

Hi,

In DMS customizing I linked a document type to vendor master and outline agreement using

object EKPO (dynpro 248) and LFA1 (dynpro 217).

After this I created an attachement and I linked it to vendor number and outline agreement.

If I click to the vendor tab (trx CV03N) system displays the vendor but if I click on the tab of the purchase order, system doesn't display

the outline agreement screen but the purchase order screen.

Is there any way to solve this issue?

Thanks

Best regards