RHSMDownloadCacher.exe airgap usage?

Alright, super confused here.
I think I’ve muddled through getting the download plug-in working. Now I’m trying to get the RHSMDownloadCacher working for an airgapped environment.

Working from the instructions at “https://www.ibm.com/developerworks/community/wikis/home?lang=en#!/wiki/Tivoli Endpoint Manager/page/Using the Red Hat Subscription Management (RHSM) download plug-in”

I think I want the RHSM plug-in to download all patches for RHEL 6 Workstation, x86_64, and to cache the downloads in sha1 format so I can store them in the sha1 folder on my airgapped BES server. How is that done?

If I use
RHSMDownloadCacher.exe --rootCertDir "d:\rhsm\certs" --download_dir d:\rhsm\downloads downloadMetadataOnly --key workstation-6-x86_64
I end up with several directories under d:\rhsm\downloads, each looks like a sha1-style name, containing a “repodata” subdirectory with several files.

If I omit the “downloadMetadataOnly” parameter, I get

RHSMDownloadCacher.exe: error: argument {showKeys | downloadMetadataOnly | buildRepo | downloadPkg | downloadByPatchId}:
 invalid choice: 'workstation-6-x86_64' (choose from 'downloadMetadataOnly', 'showKeys', 'buildRepo', 'downloadPkg', 'do
wnloadByPatchId')

If I use the buildRepo option, it looks like the files are downloaded, keeping their .rpm names and the repodata is generated (like this was a custom yum repository maybe?). That makes it difficult to compare the downloads with existing sha1 content, and I’m not sure the system would even use sha1 caching if I copied the files there…

With the old RHELDownloadCacher, I would cache all downloads for fixlets in the Red Hat sites, and copy the resulting sha1 files to my airgapped server so the downloads were available when my operators sent actions.

How do we precache downloads with the new scheme? Do I have to create custom repositories? Do I have to identify every Package or PatchID to download? How do I ensure that only updated packages are downloaded (the RHELDownloadCacher compared the downloads to existing sha1 content to avoid re-downloading)?