The theme is very old. I personally got it to know one year ago with multipe
The question to solve is :
How do you add the necessary win7 explorer to your project?
The first reply "just include it" looks good, but to work so, is illegal. explorer.exe is M$ copyrighted, and distribution is not allowed.
As an alternity, methods are known, where the end user patches his own legal copy of win8 explorer.exe to become win7 explorer.exe using some delivered "patch-control-information"
On the first view ok. No distributing of non-distributable files.
On the second view: What about the patch?
IMO the logical contents of the patch control file is also M$ proprietary, and therefore this method is also not legal.
My way is this:
- Download something from an official M$ download URL
- Patch some files when necessary with "non-proprietary" contents.
In reality that means:
- Extract install.wim from a M$ legitimated Win7 iso in the internet
- Extract explorer.exe and explorer.exe from this install.wim
- Patch explorer.exe to use wrp32.dll rather than some original M$ dlls
This is done by a simple command line batch (I'm sure Wonko likes the way how to skip user input 
Or has he a better expert suggestion?)
set language=en-US if not [%1]==[] set language=%1 if not exist %language% mkdir %language% if not exist install.wim java -jar re7zip.jar /t=udf /a=http://msft.digitalrivercontent.net/win/X17-59183.iso /e=sources\install.wim /o=install.wim java -jar re7zip.jar /t=wim /a=install.wim /e=1\Windows\explorer.exe /o=explorer.exe java -jar re7zip.jar /t=wim /a=install.wim /e=1\Windows\%language%\explorer.exe.mui /o=%language%\explorer.exe.mui patchex7<stroke.txt
The batch will be published soon, after final tests, in the reboot.pro download area.
Peter