WMI and StdRegProv

[scheru]

I am trying to access the stdregprov using the COM interface using C++. I am
unsuccessful in invoking the Put method that initializes the variables before
calling the Exec method of IWbemClassObjec t.
The code is as follows
BSTR bsClassName = SysAllocString( L"Root\\default :StdRegProv");
BSTR bsMethodName = SysAllocString( L"GetStringValu e");

pClass = NULL;
hres = pSvc->GetObject(bsCl assName, 0, NULL, &pClass, NULL);
pInParamsDefini tion = NULL;
hres = pClass->GetMethod(bsMe thodName, 0, NULL, &pInParamsDefin ition);

pClassInstance = NULL;
hres = pInParamsDefini tion->SpawnInstance( 0, &pClassInstance );

VARIANT var;
BSTR ArgName = SysAllocString( L"hDefKey");
// set registry root
VariantClear(&v ar);
var.vt = VT_I4;
var.lVal = 0x80000002;
hres = pClassInstance->Put(ArgName, 0, &var, 0);

// set registry key
VariantClear(&v ar);
var.vt = VT_BSTR;
var.bstrVal =
SysAllocString( L"SYSTEM\\Curre ntControlSet\\C ontrol\\CrashCo ntrol");
hres = pClassInstance->Put(L"sSubKeyN ame", 0, &var, 0);
// set registry key
VariantClear(&v ar);
var.vt = VT_BSTR;
var.bstrVal = SysAllocString( L"AutoReboot ");
hres = pClassInstance->Put(L"sValueNa me", 0, &var, 0);
VariantClear(&v ar);

DWORD dwValue = -1;
hres = pSvc->ExecMethod(bsC lassName, bsMethodName, 0,NULL, pClassInstance,
&pOutParams, NULL);
Are there any samples to do the something similar