[SR-Users] uac "restore_mode" is auto: effective when using core variables?

[Andrew Pogrebennyk]

Per my understanding the uac module stores the "vsf" parameter in
Record-Route and should be able to update the From/To URIs automatically
in all in-dialog requests that carry this parameter.
http://kamailio.org/docs/modules/stable/modules/uac.html#uac.p.restore_mode

“auto” - all sequential requests and replies will be automatically
updated based on stored original URI. For this option you have to set
“modparam("rr", "append_fromtag", 1)”.

What makes me wonder is: does that only work in From/To was changed by
uac_replace_from()/uac_replace_to() or also when assigning directly to
the $fu and $tu variables? I'm changing those variables and I am using
restore_mode auto but that does not change anything in in-dialog ACK.
I presume this is expected behavior because I'm not using uac when
assigning to variables, isn't it?

Thanks.
Andrew