Force ReadyBoost to be Persistent Across Reboots?

Question

Possible Duplicate:
How to stop ReadyBoost from rebuilding cache after every restart on SD cards and flash drives?

I'm running Windows 7 x64. I'm using ReadyBoost with a lot of flash memory (an 8 gig drive plus a 2 gig drive) and according to Performance Monitor, I've never utilized more than about 3 gigs of it (Bytes cached) or 1.5 gigs (Cache space used, after compression). By default, it seems like Windows rebuilds the ReadyBoost cache from scratch on every reboot. Is there a way to tell Windows that I want the ReadyBoost cache to be persistent across reboots? I understand that this would cause problems in any of the following scenarios, which is probably MS's justification for making it non-persistent by default, though none of them apply to me:

• Multibooting OS's that use ReadyBoost.
• Moving the flash drive between computers between reboots.
• If you're concerned about privacy issues w.r.t. the ReadyBoost cache.