There isn't an OOTB loader to create EPMDescribeLink links. That was one of the many loaders I've written, and it really isn't bad.
Here's my csvmapfile entry:
EPDMPartEPMDocDescribe~create~com.xxx.createPartEPMDocDescribes~docNumber~docVersion~docIteration~docCageCode~partNumber~partVersion~partIteration~partView~cageCode
Then you basically go through, with the info from the loadFile, and find your WTPart and EPMDoc. After that, it's pretty much:
//create the epmDescribe link
link = EPMDescribeLink.newEPMDescribeLink( part, epmDoc );
//save the created link
PersistenceServerHelper.manager.insert(link);
Thanks
Chris