Cloning a Tier with an additional "virtual external tier" from production to test

Hi.

We've implemented a virtual external web-tier for our E-Business-Suite according to Case History: Implementing a Reverse Proxy Alone in a DMZ Configuration - R12 [ID 726953.1].

This is working fine so far, so we now have a EBS with both an internal App and a second, virtual web tier that is accessed through (Reverse)Proxys through our DMZ (Both instances are on the same machine). We'd now like to clone this environment from Product to a new Testing-System. Unfortunately, I'm not sure on how to achieve this. 

We're cloning according to Metalink-Note 406982.1. My first thought would be to call adpreclone twice: First on the "real" ADMIN_SCRIPTS_HOME and then changing to the second env with ". setenvexternal.sh", switching to $ADMIN_SCRIPTS_HOME and doing a second adpreclone. (This would be a modification of 2.1.b of the mentioned rapid-clone-guide). But I've definitely no idea on how to do the cloning-steps after having copied my data to the new machine (Step 3.b of the tutorial). For a normal instance, my $COMMON_TOP/clone/context/apps would have a CTXORIG.xml derived from my original Context. This file should be used when calling " perl adcfgclone.pl appsTier" shouldn't it?But how would I