installscript configure website to use specific version of ASP.NET

After managing to register ASP.NET 1.1 the next step was to tell the newly installed website to use version 1.1 of ASP.NET, rather than the default.

This was done with the following function.

function ConfigureAspDotNetOnePointOne(hMSI)
 STRING svRootVer, svMajMin, szApplicationPath, szVirtDir, szK, szS;
 NUMBER nvType, nvSize, nIsFlag; 
begin                                                  
//Check the registry to see how/if ASP.NET 1.1 is configured with IIS 
//We'll be looking in the HKLM hive
RegDBSetDefaultRoot(HKEY_LOCAL_MACHINE);

//initialise to be sure of what started with 
svRootVer = "";
           
//Try and read a value from the registry, which will exist if it is installed and registered
RegDBGetKeyValueEx("SOFTWARE\\Microsoft\\ASP.NET", "RootVer", nvType, svRootVer, nvSize);
                 
StrSub(svMajMin, svRootVer, 0, 4);
                  
//If path key does not exists, ASP.NET 1.1 is not registered with IIS           
if (svMajMin != "1.1.") then  
 //Check it exists
 nIsFlag = FILE_EXISTS;
 szApplicationPath = WINDIR ^ "\\microsoft.net\\framework\\v1.1.4322\\aspnet_regiis.exe";
 //Ensure that the path or filename is correctly enclosed in quotation marks,
 LongPathToQuote(szApplicationPath, FALSE);
 //Check if the exe file exists
 if (Is (nIsFlag, szApplicationPath) == TRUE) then    
   //Get the name of the virtual dir          
   nvSize = 256;
   MsiGetProperty(hMSI, "IIS_VIRTUAL_DIR", szVirtDir, nvSize);
   //build command line arguments                                     
   szK = ' -k "W3SVC/1/Root/' + szVirtDir + '"'; //must quote as may contain spaces                                  
   szS = ' -s "W3SVC/1/Root/' + szVirtDir + '"';
                                         
   //Register with IIS without script paths         
   LaunchAppAndWait(szApplicationPath, " -ir", WAIT);   
   //Remove any script path associations defaulted to new web application  
   LaunchAppAndWait(szApplicationPath, szK, WAIT);                    
   //Associate new web application with desired ASP.NET version (1.1)    
   LaunchAppAndWait(szApplicationPath, szS , WAIT);       
 endif;     
endif;

end;

I run this as a custom action in the Install Exec Sequence, after ScheduleReboot and with the condition 'Not Installed',