iDRAC7 virtual media - USB flash drive won't map

I'm testing a new T320 with an iDRAC7. Management station is Win 7 with IE 9. With the virtual console open I select Virtual Media > Launch Virtual Media. A USB flash drive is mounted on the management station. The flash drive shows up in the virtual media window as drive E and a new drive appears on the managed system named "CD Drive (E:)". If I select the Mapped checkbox for the flash drive, nothing changes in the Details pane, both entries still say "Not Mapped". Likewise the drive contents are not accessible from the managed station.

After some digging around it appears this behavior happens when the plug-in type is set to Native uner Console > Virtual Console. If the plug-in type type is changed to Java then the flash can be mapped as expected.

So I'm wondering if there is something that can be done to make this work with the native (ActiveX) plug-in type as I would prefer not to use Java.

The image below shows the problem - the checkbox for the USB flash drive is selected but the drive is not mapped, it just shows as an empty CD drive on the target system.