Add this text to the registry and you'll be able to add your DLLs to the
GAC by right clicking on them:
[HKEY_CLASSES_ROOT\dllfile\shell\gacutil\command]
@="c:\\windows\\Microsoft.NET\\Framework\\v1.1.4322\\gacutil.exe /i \"%1\""
Found from:
http://biztalkia.blogspot.com/2005/12/easier-way-to-add-dll-to-gac.html