SQL Server 2005 Unattended Install Bootstrapper Fails On French XP System

The scenario I have is as follows:

Our product ships with a bootstrapper that installs SQL Server 2005 silently for our clients - basically it's a pre-req which we load for them if it's not already installed.

The bootstrapper supplies the service account identity parameters for the SQL Server install command line in English. It supplies the local system account (NT AUTHORITYSYSTEM).


The problem occurs when we tried to install the product onto a French version of XP. We got the error message "SQL Server setup could not validate the service accounts. Either the service accounts have not been provided for all the services being installed, or the specified username or password is incorrect. For each service, specify a valid username, password, and domain, or specify a built-in system account."


Having read the page http://msdn2.microsoft.com/en-us/library/ms143504.aspx#Localized_service_names we have discovered that the system account identity has a different name for French (AUTORITE NTSYSTEM) along with some other languages ... but we're not sure how to resolve the problem.

Can anyone out there tell me whether we ...
1) Can get the machine being installed on to tell us the local system account identity so we can substitute it into our command line in the bootstrapper?
2) Have to write a different bootstrapper for each language that names the local system account identity differently?
3) Have overlooked some other solution?


Also, does anyone know how many languages and which they are that give the local system account a name that's different to "NT AUTHORITYSYSTEM"??

Thanks,
Sara

<EDIT>

Sorry, omitted a vital bit of information. The bootstrapper is written in C++.
We know the .NET code to retrieve an NT account given a well known SID. Can we do the same in C++ somehow??
</EDIT>