Alright, here's the answer I got from the RT Support:
"Dear customer,
Thank you for your inquiry.
The new driver is not ready yet.
We have not tested the Archos JBMM with the CFU1U.
Is the Archos JBMM recognized as standard mass storage drive on PC/Mac without special driver? If so, is it recognized as removable drive or normal hard drive?
Actually, we have one customer who has the Tripper drive.
Please see below about the Tripper drive.
http://www.mittoni.com/catalog/produ...oducts_id/1243
He had difficulty to use his drive through the CFU1U,
but eventually he can use it.
Please refer to his comment:
http://forums.dpreview.com/forums/re...essage=4622190
Lately, we found that even if the normal hard drive is formatted as
super floppy drive, it is recognized on PDA.
If the Archos JBMM is normal hard drive and if you can format the drive as super floppy drive, it might be going to work.
But this is just my thought. Since we have not tested the Archos JBMM, I cannot tell if it will work or not.
I hope this answers your questions.
Sincerely,
Tsuki."
I will reply of course telling them how the Archos is identified when connected (USB Mass Storage Removable HDD), and I will wait to see if they have any success at making it work with their CF USB card ;)