[exim] How to fix tod_log in variable

Hello everybody,

I need to identify the couple FROM - RCPT in the rcpt acl where there is
no ID_message.

I need to fix tod_log in a variable and a randomize char in an otherone.

I' ve got this in the checkmail acl :

IDENTIFIANT = ${expand:$tod_log}
set acl_m3 = ${readfile{/proc/sys/kernel/random/uuid}}

Later in rcpt_acl when I read variable :

acl_m3 = XXXXXXXXX-XXXX-XXXX-XXXX     OK
IDENTIFIANT = ${expand:$tod_log}

So the value of tod_log is not fix in the variable the first time and
change when I call it.

I've try with acl_m3=${expand:$tod_log} but it give the same thing.

Thanks a lot for the solution to fix tod_log in a variable.
Sam.