iSCSI & memory cache

[Greg]

hi there,

I'm setting up an iSCSI server on Trixie. My plan is to export a block 
device with memory caching enabled for both reads and writes. 
Unfortunately, no matter what I try, targetcli always shows write-thru 
mode (for block devices). is there any way to change this? Different 
software?

Thanks in advance for any help
Greg