How do I load Windows printer drivers on a Samba 4 print server?

Premise / status: I've set up Samba 4 as an AD controller, and, according to the instructions on the howto, have established a [print$] share that should allow me to "upload printer drivers for Point'n'Print driver installation." The printers are visible from the Windows client, but the server does not have Windows drivers available so drag and drop installation won't work.

Problems / deviation from the instructions:

• If I attempt to load the driver with the [print$] share permissions set as per the howto, (755 server side, samba config includes 'writeable = yes') I get an access denied error.
• If I set the [print$] share permissions wide open on the server (777) and use the Windows 7 interface to make sure that either Domain Admins or even Everyone has full control, drivers will appear to begin installation and then fail with errer 0x0000001f. It does not appear that any files are actually placed on the server.

I've tried this with different printers and drivers. The user account is a Domain Admin and that group was granted print operator privileges. I can even just shove random text files into the [print$] share from Windows.

Sub-question: Is there / shouldn't there be a way to have write permissions through the Samba4 server without setting the local unix permissions wide open?

Main question: What do I actually need to do in order to get the print drivers to installed on the server?