Error launching batch file from within AppV 5 bubble

So we have an application that requires the "%CLIENTNAME%" variable to be passed to it in it's exe string.  The string looks like so:

prowin32.exe -p \\nas\cfgstart.p -param S,%CLIENTNAME%,120n,citrix,a92,10920 -wy

The issue we have is APPV does not seem to get that variable and pass it to the program.  So when the program starts, it makes %clientname% folders in a temp directory and we can't have two %clientname% folders in the same directory so only one instance of the application can be launched *period* if we do it this way, as opposed to one per server.

To resolve this issue I wrote a script that will pass the %CLIENTNAME% variable to AppV by ripping it out of the registry:

=======================================================

ECHO Launching Centricity...

for /f "tokens=1-3" %%A IN ('reg query "HKCU\volatile environment" /s ^| findstr /i /c:"CLIENTNAME"') DO SET CLIENTNAME=%%C

prowin32.exe -p \\nas\cfgstart.p -param S,%CLIENTNAME%,120n,citrix,a92,10920 -wy

=======================================================

This worked for AppV 4.6 without issue.  Now with AppV 5 I get an error, PATH NOT FOUND when trying to launch this script.

To verify the path exists in the app I ran the following commands:

The powershell commands put me in the AppV 5 bubble then opened a command prompt.  From the command prompt I can see the directory that is missing.  Going back to procmon I was curious to see what command it was launching.  It was launching this:

cmd /c ""C:\ProgramData\Microsoft\AppV\Client\Integration\3230251A-5B8E-47EF-8378-986B2A492D05\Root\VFS\Common Desktop\MyApps\BDM Pharmacy v9.2\Centricity Pharmacy Test on rxpv91cal.cmd" /appvve:3230251A-5B8E-47EF-8378-986B2A492D05_03CA3F94-F318-4693-A7E3-038DB30E6C70"

This command was failing.  It appears that when you are launching the .cmd file directly AppV 5 starts the cmd.exe *outside* the AppV bubble and it doesn't connect to the appvve.  To correct this I tried this command line:

cmd /c "cmd.exe /c "C:\ProgramData\Microsoft\AppV\Client\Integration\3230251A-5B8E-47EF-8378-986B2A492D05\Root\VFS\Common Desktop\MyApps\BDM Pharmacy v9.2\Centricity Pharmacy Test on rxpv91cal.cmd" /appvve:3230251A-5B8E-47EF-8378-986B2A492D05_03CA3F94-F318-4693-A7E3-038DB30E6C70"

Success!  It launched successfully and saw the directory and everything was good there after.  So let that be a lesson to other AppV 5 package makers, if you need a pre-launch script you may need to modify your published icon to put another cmd.exe /c before the command file for it to start in the bubble.

A very good AppV blog has already discovered this issue and came back with a better fix than mine:
http://blogs.technet.com/b/virtualvibes/archive/2013/10/17/the-issues-of-sequencing-bat-shortcuts-in-app-v-5-0.aspx