Create a launcher stub?

When creating a Portable App, if I have the EXE in the App/[program name] folder, like in most if not all of the official applications released, how do I create a launcher stub program, like "7-ZipPortable.exe" which points to App\7-Zip\7zFM.exe, for example?

I have a few DLL files which need to be in the same directory as the executable file, but if I leave them in the base directory, they don't get picked-up by PA.c Installer Portable program. If I put the DLLs into the App\[appname] folder, but put the EXE file in the base folder, then the installed app complains about the missing DLL files, and if I put them all into the App\[appname] folder, than PA.c Installer complains about no executable file in the base folder.

Is there an NSIS command or script needed to create that launcher stub? or perhaps there is a separate developer program needed to create the launcher?

As an aside, the program is a stand-alone freeware program (ie. it doesn't use the registry or any ini files), but it needs several commercial DLL files, which are installed into a particular location when iTunes is installed. Since these support files are not distributable, is it possible to have a post-install script of some kind check for the existence of the source files, and copy then (if they do exist), into the portable app's folder?

--Aaron