use of variables in ACL (1 reply)

Is there anyway to use:

http-request set-var()

to set a var for later use in forming an ACL?

I've tried all the prefixes to make the variable survive past http
processing, but the ACL is always rejected by the config check.

<snip>
http-request set-var(txn.my_v) base,sdbm,mod(100)
acl test_threshold txn.my_v lt 10
</snip>