Archiving MM_EKKO (Purchasing documents with attachments)

We would like to start archiving MM_EKKO Purchasing documents. The units have been attaching items, quotes for example, to the purchasing documents. The attachments currently exist within the R/3 data base. If we archive MM_EKKO items the attachments will be lost. What we need to do is identify all the attachments and move them to content server.

Where are these attachment stored i.e in which table.?

Is there any procedure for archiving attachments?