Installing Thumbnail shell extension ?

Hi I am trying to create a shell extension for generation thumbnails for
an image type called ics.

I have a passing familiarity with com and have creating an object that implements
IExtractImage and IPersistFile in c.

The code for this is here


http://193.61.195.247:82/ThumbnailGenerator.zip


I have compiled this as a dll.
Most of it is boilerplate it should if working return a small black thumbnail for now.
I am not sure if the code is correct as I not sure how to install the extension.

I have created registry entries like so

HKEY_CLASSES_ROOT\CLSID\{5B5780E2-DF51-4f20-8566-B43CD254EA83}
Default REG_SZ IcsThumbnailer


HKEY_CLASSES_ROOT\CLSID\{5B5780E2-DF51-4f20-8566-B43CD254EA83}\InprocServer32
Default REG_SZ c:\Documents and Settings\Glenn\Desktop\Working

Area\IcsShellExtension\IcsThumbnailer.dll

ThreadingModel REG_SZ Apartment


I have also created

HKEY_CLASSES_ROOT\icsfile\ShellEx\
{E357FCCD-A995-4576-B01F-234630154E96} REG_SZ {5B5780E2-DF51-4f20-8566-B43CD254EA83}


What is there left todo ?


I have called Regsvr32 on the dll as well. I am not sure sure if this is neccessary ?


Can someone please help with advice on how to install
a thumbnail shell extension and if possible howto debug it.
The web sites I have found have not been great.

Thank for any help.

Glenn