BDC/BAPI for vendor master  to capture attachments/addtional telephon

additional phone number, fax numbers and mail  addresses can be loaded with ADRMAS Idoc

Please read OSS note 306275 and 384462 for the details

if you are using document management system to store the attachments then SAP has a IDOC too:

SAP Library - Integrated Distributed PDM Solution (ID PDM)

if you are just using the generic object service for your attachments the see this blog:

Generic object services (GOS) - in Background