Package synchronisation and EPM attachments

So we are doing the following for one particular customer:

1. publish DXF and DWG using afterEDRloader
2. rename and copy to EPMDocument attachments (for collection in package delivery)
3. create package containing DXF, DWG, pdf and ZIP only (ZIP to capture multisheet DXF & DWG)
4. send package as email attachment

I can see that the zip package action triggers a package synchronisation wvs job, which looks like it re-publishes the epm document, presumably to synchronise any attributes which might have been changed since the package was created?

As we are using the package ultimately to send the DXF, DWG and pdf content, how do we ensure that the DXF and DWG files are synchronised, at the moment I cant see them being republished during the synchronisation, in addition I dont see the afterloader being called during the synchronisation.