Transferring Files To Or From Device Connected To A USB 2.0 Hub

I run an ACER Aspire X3950 with Windows 7 Ultimate 64bit. I purchased a "RAYGO eXtreme Hard Drive enclosure (SATA to USB)" and installed within it a 1 Terabite HDD that was working (and can work) flawlessly in a different PC. The HDD is about 85% empty. For no apparent reason, most of the time when I (try to) transfer large files to the external HDD, the latter stops working. However, I've been able to transfer (blocks of) files of more thann 30 Gb without a hitch.

When the external HDD does stops working, Device Manager shows "Unknown device". When it works, Device Manager shows two instances of "USB Mass Storage Device". If I restart the PC, most of the time the external HDD is ignored and not even the "Unknown device" entry appears. The closest thing to a solution I found at "Problems may occur when you try to transfer files to or from a device that is connected to a USB 2.0 hub", where they state:

Code: Resolution for Windows 7
To resolve this problem in Windows 7, add a EnHcSoftRetry registry entry with a DWORD value of 1 under the following registry subkey:
HKEY_LOCAL_MACHINESYSTEMCurrentControlSetEnumPCI<hw id><instance id>Device Parameters

Note To obtain <hw id> and <instance id>, open the Device Manager property page for each EHCI USB host controller, click the Details tab, and then select Device Instance Path in the list. Most systems have only one or two EHCI host controllers, so this should not be too difficult. To no avail, I've tried placing the EnHcSoftRetry registry entry both as part of the "Device Parameters" entry and as a sub of it. I've tried using DWORD and QWORD to no avail, too.